feat(poll): make exact transitions idempotent

README.md

@@ -50,6 +50,96 @@ and authenticated API routes for:
 - signed participation links for reduced/no-Access participation
 - context and workflow metadata for modules such as Scheduling
 
+## Governed signed participation
+
+The v0.1.10 contract lets a consuming module bind an invitation to an exact
+response gateway (`module_id`, `resource_type`, and `resource_id`) and snapshot
+generic participation rules onto it. A bound invitation cannot use the legacy
+`GET /poll/public/{token}` or `POST /poll/public/{token}/responses` routes: both
+return the same generic not-found response used for invalid, expired, and
+revoked links. There is deliberately no browser-facing Poll bypass when the
+owning gateway is missing.
+
+That boundary is Poll-wide. Setting `context_module` declares a module-owned
+Poll; for a standalone Poll, its first governed invitation opts the whole Poll
+into governed participation. From then on, direct authenticated response
+writes, ordinary invitation creation, and every legacy public link fail closed,
+including links created before governance was enabled. Governed invitations can
+only be created through the in-process participation capability and their
+gateway must match the Poll's declared module resource (or the standalone
+Poll's first gateway). Polls that never opt into governance retain their
+ordinary authenticated and signed-link behavior.
+
+Module ownership also protects management boundaries. Generic Poll update,
+lifecycle, option, and invitation-revocation paths cannot mutate an owned Poll,
+and generic raw-response and invitation projections cannot bypass the owning
+module's privacy policy. The in-process capability supplies the exact module,
+resource type, and resource id again for every mutation; Poll compares that
+owner while holding its row lock. Aggregate result summaries remain reusable.
+
+Consumers resolve and submit bound invitations through the
+`poll.participation_gateway` in-process capability. The policy covers:
+
+- at most one non-`unavailable` selection
+- whether `maybe` is accepted
+- a maximum number of definitive participants per option
+- response comments (trimmed and limited to 4,000 characters)
+- email for anonymous participants
+- an anonymous-password verification requirement
+
+For availability polls, `available` reserves capacity while `maybe` does not.
+Poll re-enforces these rules under its Poll-row lock, so concurrent final-place
+claims serialize on PostgreSQL. A gateway-owned password never crosses the
+capability boundary: the owning module stores the sole salted verifier,
+throttles attempts before checking it, and supplies only the
+`anonymous_password` verification attestation. Poll rejects secret-like
+invitation/response metadata and stores no password column.
+
+Authenticated module flows do not need to retain a public bearer token. They
+can resolve and submit by exact tenant, Poll, governed invitation, gateway, and
+respondent identifiers. Poll rejects mismatched identities and applies the same
+Poll-row lock and policy checks used by the public-token path. A consumer can
+lazily create that governed invitation, retain only its id, and discard the raw
+token when no public link is needed.
+
+An owning gateway can update a non-revoked invitation's expiry in place. A past
+timestamp expires the existing link immediately; a later future timestamp or
+`null` reactivates that same link without exposing or rotating its bearer token.
+Revoked invitations remain revoked, and exact retries are idempotent.
+
+The capability also supports durable invitation-scoped idempotency keys,
+response prefill, option addition/removal, and invitation revocation. Exact
+submission retries return the existing response; key reuse with different
+content is rejected. Because a response is an editable resource, replay returns
+its current representation rather than an immutable snapshot of the first
+submission. Option removal and option changes invalidate only answers bound to
+that option, and repeated removal/revocation is an idempotent replay even after
+the Poll has moved out of an editable lifecycle state.
+
+Owning modules can also retire a participant's responses through the optional
+response-retirement extension. Retirement is idempotent and soft-deletes the
+live rows so aggregation and capacity checks stop counting them, while answers
+and a reason/source retirement record remain available for audit. The boundary
+accepts only server-trusted respondent or invitation identities and rejects
+secret-like metadata.
+
+## Identified response invariant
+
+Poll stores at most one active response for each identified respondent in a
+Poll. PostgreSQL and SQLite enforce this with the partial unique index
+`uq_poll_responses_active_respondent`; anonymous and tombstoned responses do
+not participate in that invariant. If two submissions race, the losing insert
+is rolled back to a savepoint and follows the ordinary update policy against
+the winning row. Unrelated integrity errors are not converted into response
+updates.
+
+The migration deterministically retains the latest active row by
+`submitted_at DESC, id DESC` and tombstones older duplicates. Apply it while
+Poll response writes are quiesced or while the platform maintenance lock is
+held. The released migration-head baseline must only be advanced as part of
+the reviewed release that includes this migration; it is not a development
+head ledger.
+
 ## Scheduling As A Poll-Backed Workflow
 
 Scheduling should use Poll as the reusable response collection primitive, not
@@ -63,6 +153,41 @@ Poll stores the shared poll/options/responses/result summary. Scheduling owns
 the domain workflow around rooms, calendars, free/busy checks, reminders,
 appointment creation, and optional Workflow integration.
 
+## Poll lifecycle
+
+Poll configures its lifecycle through the separate, pure transition engine in
+`backend/transitions.py`. The default policy is:
+
+- `draft` → `open` or `archived`
+- `open` → `draft`, `closed`, or `archived`
+- `closed` → `open`, `decided`, or `archived`
+- `decided` → `open`, `decided` (an explicit re-decision), or `archived`
+- `archived` → the status from which the Poll was archived
+
+Reopening and archiving preserve responses, close history, and decision
+metadata. Every applied transition has a Poll-owned lifecycle audit record.
+Re-deciding always appends a record and supersedes the current decision. An
+exact retry carrying the same `Idempotency-Key` is a no-op and returns the
+original transition record; reusing that key for a different action or option
+is rejected. A command whose requested lifecycle state already holds is also
+an idempotent domain no-op, even without an idempotency identity. It returns
+the current Poll with `replayed=true` and `transition=null`, does not append a
+lifecycle audit record, and is emitted only to operational logs as duplicate
+command telemetry. A new idempotency key supplied for such an audit-free no-op
+is not consumed. Re-deciding with a different option remains a new auditable
+action; repeating the current decision is a no-op.
+
+Poll API representations expose every lifecycle action with its availability
+and, when unavailable, the policy reason. Management clients can use the
+`GET /poll/polls/{poll_id}/transitions` endpoint to read the durable history
+instead of duplicating the matrix in their UI.
+
+Polls created through the v0.1.9 contract start in `draft` or `open`; later
+states are entered through the transition engine. Older archived rows may not
+contain the status from which they were archived. Their prior state cannot be
+inferred safely, so unarchive restores them to the least-permissive `draft`
+state and marks that legacy fallback explicitly in the audit metadata.
+
 ## Development Install
 
 ```bash
@@ -76,3 +201,11 @@ Focused manifest verification:
 cd /mnt/DATA/git/govoplan-poll
 PYTHONPATH=src:/mnt/DATA/git/govoplan-core/src /mnt/DATA/git/govoplan-core/.venv/bin/python -m unittest discover -s tests
 ```
+
+Run the optional two-session PostgreSQL race check against a disposable or
+development database account that may create schemas:
+
+```bash
+GOVOPLAN_POLL_TEST_POSTGRES_URL=postgresql+psycopg://user@localhost/database \
+  /mnt/DATA/git/govoplan/.venv/bin/python -m pytest -q tests/test_response_uniqueness.py
+```

pyproject.toml

@@ -4,14 +4,14 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "govoplan-poll"
-version = "0.1.8"
+version = "0.1.11"
 description = "GovOPlaN lightweight poll and availability decision module seed."
 readme = "README.md"
 requires-python = ">=3.12"
 license = { file = "LICENSE" }
 authors = [{ name = "GovOPlaN" }]
 dependencies = [
-  "govoplan-core>=0.1.8",
+  "govoplan-core>=0.1.11",
 ]
 
 [tool.setuptools.packages.find]

src/govoplan_poll/__init__.py

@@ -2,4 +2,4 @@
 
 __all__ = ["__version__"]
 
-__version__ = "0.1.8"
+__version__ = "0.1.11"

src/govoplan_poll/backend/capabilities.py

@@ -0,0 +1,825 @@
+from __future__ import annotations
+
+from collections.abc import Mapping, Sequence
+from datetime import datetime
+
+from pydantic import ValidationError
+
+from govoplan_core.core.poll import (
+    PollAnswerRef,
+    PollCapabilityError,
+    PollCreateCommand,
+    PollInvitationCommand,
+    PollInvitationRef,
+    PollOptionOrderCommand,
+    PollOptionRequest,
+    PollOptionRef,
+    PollOptionUpdateCommand,
+    PollRef,
+    PollResponseRef,
+    PollResponseRetirementCommand,
+    PollResponseRetirementRef,
+    PollSchedulingProvider,
+    PollSubmitResponseCommand,
+    PollUpdateCommand,
+)
+from govoplan_poll.backend.participation import (
+    ANONYMOUS_PASSWORD_REQUIREMENT,
+    PollGovernedInvitationCommand,
+    PollGovernedResponseCommand,
+    PollGovernedResponseRef,
+    PollInvitationExpiryRef,
+    PollInvitationRevocationRef,
+    PollOptionMutationRef,
+    PollParticipationContextRef,
+    PollResponseGatewayRef,
+)
+from govoplan_poll.backend.participation_service import (
+    governed_invitation,
+    governed_invitation_by_id,
+    participation_policy_payload,
+    participation_policy_ref,
+    response_for_invitation,
+    response_gateway_payload,
+    response_gateway_ref,
+    response_metadata,
+    submit_governed_poll_response,
+    submit_authenticated_poll_response,
+    update_governed_invitation_expiry,
+)
+from govoplan_poll.backend.db.models import PollInvitation
+from govoplan_poll.backend.schemas import (
+    PollAnswerInput,
+    PollCreateRequest,
+    PollDecisionRequest,
+    PollInvitationCreateRequest,
+    PollOptionInput,
+    PollSubmitResponseRequest,
+)
+from govoplan_poll.backend.service import (
+    PollError,
+    PollMutationOwner,
+    close_poll,
+    add_poll_option,
+    create_poll,
+    create_poll_invitation,
+    decide_poll,
+    get_poll,
+    get_poll_response_for_respondents,
+    list_poll_responses,
+    open_poll,
+    poll_mutation_owner,
+    poll_owner_ref,
+    poll_result_summary_by_id,
+    response_datetime,
+    retire_poll_responses,
+    remove_poll_option,
+    reorder_poll_options,
+    revoke_poll_invitation_with_replay,
+    set_poll_workflow_context,
+    submit_poll_response,
+    update_poll_snapshot,
+    update_poll_option,
+)
+
+
+def _poll_ref(poll: object) -> PollRef:
+    return PollRef(
+        id=poll.id,
+        status=poll.status,
+        options=tuple(
+            PollOptionRef(id=option.id, position=option.position)
+            for option in sorted(
+                (option for option in poll.options if option.deleted_at is None),
+                key=lambda item: (item.position, item.id),
+            )
+        ),
+    )
+
+
+def _command_owner(command: PollCreateCommand) -> PollMutationOwner | None:
+    context = (
+        command.context_module,
+        command.context_resource_type,
+        command.context_resource_id,
+    )
+    if not any(value is not None for value in context):
+        return None
+    return poll_owner_ref(
+        module_id=command.context_module,
+        resource_type=command.context_resource_type,
+        resource_id=command.context_resource_id,
+    )
+
+
+def _stored_owner(
+    session: object,
+    *,
+    tenant_id: str,
+    poll_id: str,
+) -> PollMutationOwner | None:
+    return poll_mutation_owner(
+        get_poll(session, tenant_id=tenant_id, poll_id=poll_id)
+    )
+
+
+def _response_invitation_id(response: object) -> str | None:
+    value = (response.metadata_ or {}).get("invitation_id")
+    return value if isinstance(value, str) else None
+
+
+def _response_ref(response: object) -> PollResponseRef:
+    answers: list[PollAnswerRef] = []
+    for answer in response.answers or []:
+        if not isinstance(answer, Mapping):
+            continue
+        answers.append(
+            PollAnswerRef(
+                option_id=answer.get("option_id"),
+                option_key=answer.get("option_key"),
+                value=answer.get("value"),
+                rank=answer.get("rank"),
+            )
+        )
+    return PollResponseRef(
+        invitation_id=_response_invitation_id(response),
+        submitted_at=response_datetime(response.submitted_at),
+        respondent_id=response.respondent_id,
+        answers=tuple(answers),
+    )
+
+
+def _participation_context_ref(
+    session: object,
+    *,
+    invitation: PollInvitation,
+    respondent_id: str | None = None,
+    participant_email: str | None = None,
+) -> PollParticipationContextRef:
+    policy = participation_policy_ref(invitation.participation_policy_)
+    response = response_for_invitation(
+        session,
+        invitation=invitation,
+        respondent_id=respondent_id,
+        participant_email=participant_email,
+    )
+    response_ref = None
+    if response is not None:
+        email, comment = response_metadata(response)
+        response_ref = PollGovernedResponseRef(
+            response=_response_ref(response),
+            participant_email=email,
+            comment=comment,
+        )
+    return PollParticipationContextRef(
+        invitation_id=invitation.id,
+        tenant_id=invitation.tenant_id,
+        poll_id=invitation.poll_id,
+        gateway=response_gateway_ref(invitation.response_gateway_),
+        policy=policy,
+        respondent_id=invitation.respondent_id or respondent_id,
+        respondent_label=invitation.respondent_label,
+        email=invitation.email,
+        response=response_ref,
+    )
+
+
+class SqlPollSchedulingProvider(PollSchedulingProvider):
+    def create_poll(
+        self,
+        session: object,
+        *,
+        tenant_id: str,
+        user_id: str | None,
+        command: PollCreateCommand,
+    ) -> PollRef:
+        payload = PollCreateRequest(
+            title=command.title,
+            description=command.description,
+            kind=command.kind,
+            status=command.status,
+            visibility=command.visibility,
+            result_visibility=command.result_visibility,
+            context_module=command.context_module,
+            context_resource_type=command.context_resource_type,
+            context_resource_id=command.context_resource_id,
+            workflow_state=command.workflow_state,
+            workflow_steps=[dict(step) for step in command.workflow_steps],
+            allow_anonymous=command.allow_anonymous,
+            allow_response_update=command.allow_response_update,
+            min_choices=command.min_choices,
+            max_choices=command.max_choices,
+            opens_at=command.opens_at,
+            closes_at=command.closes_at,
+            options=[
+                PollOptionInput(
+                    key=option.key,
+                    label=option.label,
+                    description=option.description,
+                    value=dict(option.value) if option.value is not None else None,
+                    metadata=dict(option.metadata),
+                )
+                for option in command.options
+            ],
+            metadata=dict(command.metadata),
+        )
+        try:
+            poll = create_poll(
+                session,
+                tenant_id=tenant_id,
+                user_id=user_id,
+                payload=payload,
+                mutation_owner=_command_owner(command),
+            )
+        except PollError as exc:
+            raise PollCapabilityError(str(exc)) from exc
+        return _poll_ref(poll)
+
+    def create_invitation(
+        self,
+        session: object,
+        *,
+        tenant_id: str,
+        poll_id: str,
+        command: PollInvitationCommand,
+    ) -> PollInvitationRef:
+        payload = PollInvitationCreateRequest(
+            respondent_id=command.respondent_id,
+            respondent_label=command.respondent_label,
+            email=command.email,
+            expires_at=command.expires_at,
+            metadata=dict(command.metadata),
+        )
+        try:
+            invitation, token = create_poll_invitation(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+                payload=payload,
+            )
+        except PollError as exc:
+            raise PollCapabilityError(str(exc)) from exc
+        return PollInvitationRef(id=invitation.id, token=token)
+
+    def create_governed_invitation(
+        self,
+        session: object,
+        *,
+        tenant_id: str,
+        poll_id: str,
+        command: PollGovernedInvitationCommand,
+    ) -> PollInvitationRef:
+        try:
+            payload = PollInvitationCreateRequest(
+                respondent_id=command.respondent_id,
+                respondent_label=command.respondent_label,
+                email=command.email,
+                expires_at=command.expires_at,
+                response_gateway=response_gateway_payload(command.gateway),
+                participation_policy=participation_policy_payload(command.policy),
+                metadata=dict(command.metadata),
+            )
+            invitation, token = create_poll_invitation(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+                payload=payload,
+                governed_capability=True,
+            )
+        except (PollError, ValidationError) as exc:
+            raise PollCapabilityError(str(exc)) from exc
+        return PollInvitationRef(id=invitation.id, token=token)
+
+    def resolve_participation(
+        self,
+        session: object,
+        *,
+        token: str,
+        gateway: PollResponseGatewayRef,
+        respondent_id: str | None = None,
+        participant_email: str | None = None,
+        participant_is_authenticated: bool = False,
+        verified_requirements: frozenset[str] = frozenset(),
+    ) -> PollParticipationContextRef:
+        try:
+            invitation = governed_invitation(
+                session,
+                token=token,
+                gateway=gateway,
+            )
+            policy = participation_policy_ref(invitation.participation_policy_)
+            if (
+                not participant_is_authenticated
+                and policy.anonymous_password_required
+                and ANONYMOUS_PASSWORD_REQUIREMENT not in verified_requirements
+            ):
+                raise PollError("Poll invitation not found")
+            return _participation_context_ref(
+                session,
+                invitation=invitation,
+                respondent_id=(respondent_id if participant_is_authenticated else None),
+                participant_email=participant_email,
+            )
+        except (PollError, ValidationError) as exc:
+            raise PollCapabilityError(str(exc)) from exc
+
+    def submit_governed_response(
+        self,
+        session: object,
+        *,
+        token: str,
+        gateway: PollResponseGatewayRef,
+        command: PollGovernedResponseCommand,
+    ) -> PollGovernedResponseRef:
+        try:
+            _invitation, response, replayed = submit_governed_poll_response(
+                session,
+                token=token,
+                gateway=gateway,
+                command=command,
+            )
+        except (PollError, ValidationError) as exc:
+            raise PollCapabilityError(str(exc)) from exc
+        email, comment = response_metadata(response)
+        return PollGovernedResponseRef(
+            response=_response_ref(response),
+            participant_email=email,
+            comment=comment,
+            replayed=replayed,
+        )
+
+    def resolve_authenticated_participation(
+        self,
+        session: object,
+        *,
+        tenant_id: str,
+        poll_id: str,
+        invitation_id: str,
+        gateway: PollResponseGatewayRef,
+        respondent_id: str,
+    ) -> PollParticipationContextRef:
+        try:
+            invitation = governed_invitation_by_id(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+                invitation_id=invitation_id,
+                gateway=gateway,
+                respondent_id=respondent_id,
+            )
+            return _participation_context_ref(
+                session,
+                invitation=invitation,
+                respondent_id=respondent_id,
+            )
+        except (PollError, ValidationError) as exc:
+            raise PollCapabilityError(str(exc)) from exc
+
+    def submit_authenticated_response(
+        self,
+        session: object,
+        *,
+        tenant_id: str,
+        poll_id: str,
+        invitation_id: str,
+        gateway: PollResponseGatewayRef,
+        respondent_id: str,
+        command: PollGovernedResponseCommand,
+    ) -> PollGovernedResponseRef:
+        try:
+            _invitation, response, replayed = submit_authenticated_poll_response(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+                invitation_id=invitation_id,
+                gateway=gateway,
+                respondent_id=respondent_id,
+                command=command,
+            )
+        except (PollError, ValidationError) as exc:
+            raise PollCapabilityError(str(exc)) from exc
+        email, comment = response_metadata(response)
+        return PollGovernedResponseRef(
+            response=_response_ref(response),
+            participant_email=email,
+            comment=comment,
+            replayed=replayed,
+        )
+
+    def add_option(
+        self,
+        session: object,
+        *,
+        tenant_id: str,
+        poll_id: str,
+        command: PollOptionRequest,
+    ) -> PollOptionMutationRef:
+        try:
+            mutation_owner = _stored_owner(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+            )
+            option, replayed = add_poll_option(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+                option=PollOptionInput(
+                    key=command.key,
+                    label=command.label,
+                    description=command.description,
+                    value=dict(command.value) if command.value is not None else None,
+                    metadata=dict(command.metadata),
+                ),
+                mutation_owner=mutation_owner,
+            )
+        except (PollError, ValidationError) as exc:
+            raise PollCapabilityError(str(exc)) from exc
+        return PollOptionMutationRef(
+            id=option.id,
+            position=option.position,
+            replayed=replayed,
+        )
+
+    def remove_option(
+        self,
+        session: object,
+        *,
+        tenant_id: str,
+        poll_id: str,
+        option_id: str,
+    ) -> PollOptionMutationRef:
+        try:
+            mutation_owner = _stored_owner(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+            )
+            option, replayed, invalidated = remove_poll_option(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+                option_id=option_id,
+                mutation_owner=mutation_owner,
+            )
+        except (PollError, ValidationError) as exc:
+            raise PollCapabilityError(str(exc)) from exc
+        return PollOptionMutationRef(
+            id=option.id,
+            position=option.position,
+            replayed=replayed,
+            invalidated_response_count=invalidated,
+        )
+
+    def revoke_invitation(
+        self,
+        session: object,
+        *,
+        tenant_id: str,
+        poll_id: str,
+        invitation_id: str,
+    ) -> PollInvitationRevocationRef:
+        try:
+            mutation_owner = _stored_owner(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+            )
+            invitation, replayed = revoke_poll_invitation_with_replay(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+                invitation_id=invitation_id,
+                mutation_owner=mutation_owner,
+            )
+        except (PollError, ValidationError) as exc:
+            raise PollCapabilityError(str(exc)) from exc
+        return PollInvitationRevocationRef(
+            id=invitation.id,
+            revoked_at=response_datetime(invitation.revoked_at),
+            replayed=replayed,
+        )
+
+    def update_invitation_expiry(
+        self,
+        session: object,
+        *,
+        tenant_id: str,
+        poll_id: str,
+        invitation_id: str,
+        gateway: PollResponseGatewayRef,
+        expires_at: datetime | None,
+    ) -> PollInvitationExpiryRef:
+        try:
+            invitation, replayed = update_governed_invitation_expiry(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+                invitation_id=invitation_id,
+                gateway=gateway,
+                expires_at=expires_at,
+            )
+        except (PollError, ValidationError) as exc:
+            raise PollCapabilityError(str(exc)) from exc
+        return PollInvitationExpiryRef(
+            id=invitation.id,
+            expires_at=response_datetime(invitation.expires_at),
+            replayed=replayed,
+        )
+
+    def submit_response(
+        self,
+        session: object,
+        *,
+        tenant_id: str,
+        poll_id: str,
+        command: PollSubmitResponseCommand,
+    ) -> PollResponseRef:
+        payload = PollSubmitResponseRequest(
+            respondent_id=command.respondent_id,
+            respondent_label=command.respondent_label,
+            answers=[
+                PollAnswerInput(
+                    option_id=answer.option_id,
+                    option_key=answer.option_key,
+                    value=answer.value,
+                    rank=answer.rank,
+                )
+                for answer in command.answers
+            ],
+            metadata=dict(command.metadata),
+        )
+        try:
+            response = submit_poll_response(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+                payload=payload,
+            )
+        except PollError as exc:
+            raise PollCapabilityError(str(exc)) from exc
+        return _response_ref(response)
+
+    def update_poll(
+        self,
+        session: object,
+        *,
+        tenant_id: str,
+        poll_id: str,
+        command: PollUpdateCommand,
+    ) -> PollRef:
+        try:
+            mutation_owner = _stored_owner(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+            )
+            poll = update_poll_snapshot(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+                title=command.title,
+                description=command.description,
+                visibility=command.visibility,
+                result_visibility=command.result_visibility,
+                allow_anonymous=command.allow_anonymous,
+                allow_response_update=command.allow_response_update,
+                closes_at=command.closes_at,
+                mutation_owner=mutation_owner,
+            )
+        except PollError as exc:
+            raise PollCapabilityError(str(exc)) from exc
+        return _poll_ref(poll)
+
+    def update_option(
+        self,
+        session: object,
+        *,
+        tenant_id: str,
+        poll_id: str,
+        option_id: str,
+        command: PollOptionUpdateCommand,
+    ) -> PollOptionRef:
+        try:
+            mutation_owner = _stored_owner(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+            )
+            option = update_poll_option(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+                option_id=option_id,
+                label=command.label,
+                description=command.description,
+                value=dict(command.value) if command.value is not None else None,
+                metadata=dict(command.metadata),
+                mutation_owner=mutation_owner,
+            )
+        except PollError as exc:
+            raise PollCapabilityError(str(exc)) from exc
+        return PollOptionRef(id=option.id, position=option.position)
+
+    def reorder_options(
+        self,
+        session: object,
+        *,
+        tenant_id: str,
+        poll_id: str,
+        command: PollOptionOrderCommand,
+    ) -> PollRef:
+        try:
+            mutation_owner = _stored_owner(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+            )
+            poll = reorder_poll_options(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+                option_ids=command.option_ids,
+                mutation_owner=mutation_owner,
+            )
+        except PollError as exc:
+            raise PollCapabilityError(str(exc)) from exc
+        return _poll_ref(poll)
+
+    def open_poll(self, session: object, *, tenant_id: str, poll_id: str) -> PollRef:
+        return self._transition(open_poll, session, tenant_id=tenant_id, poll_id=poll_id)
+
+    def close_poll(self, session: object, *, tenant_id: str, poll_id: str) -> PollRef:
+        return self._transition(close_poll, session, tenant_id=tenant_id, poll_id=poll_id)
+
+    def decide_poll(
+        self,
+        session: object,
+        *,
+        tenant_id: str,
+        poll_id: str,
+        option_id: str | None,
+    ) -> PollRef:
+        try:
+            mutation_owner = _stored_owner(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+            )
+            poll = decide_poll(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+                payload=PollDecisionRequest(option_id=option_id),
+                mutation_owner=mutation_owner,
+            )
+        except PollError as exc:
+            raise PollCapabilityError(str(exc)) from exc
+        return _poll_ref(poll)
+
+    def get_poll(self, session: object, *, tenant_id: str, poll_id: str) -> PollRef:
+        try:
+            return _poll_ref(get_poll(session, tenant_id=tenant_id, poll_id=poll_id))
+        except PollError as exc:
+            raise PollCapabilityError(str(exc)) from exc
+
+    def set_workflow_context(
+        self,
+        session: object,
+        *,
+        tenant_id: str,
+        poll_id: str,
+        workflow_state: str,
+        workflow_steps: Sequence[Mapping[str, object]],
+        context_module: str,
+        context_resource_type: str,
+        context_resource_id: str,
+    ) -> PollRef:
+        try:
+            mutation_owner = _stored_owner(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+            )
+            requested_owner = poll_owner_ref(
+                module_id=context_module,
+                resource_type=context_resource_type,
+                resource_id=context_resource_id,
+            )
+            poll = set_poll_workflow_context(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+                workflow_state=workflow_state,
+                workflow_steps=[dict(step) for step in workflow_steps],
+                context_module=context_module,
+                context_resource_type=context_resource_type,
+                context_resource_id=context_resource_id,
+                mutation_owner=mutation_owner,
+                requested_owner=requested_owner,
+            )
+        except PollError as exc:
+            raise PollCapabilityError(str(exc)) from exc
+        return _poll_ref(poll)
+
+    def result_summary(self, session: object, *, tenant_id: str, poll_id: str) -> Mapping[str, object]:
+        try:
+            return poll_result_summary_by_id(session, tenant_id=tenant_id, poll_id=poll_id)
+        except PollError as exc:
+            raise PollCapabilityError(str(exc)) from exc
+
+    def list_responses(self, session: object, *, tenant_id: str, poll_id: str) -> tuple[PollResponseRef, ...]:
+        try:
+            projection_owner = _stored_owner(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+            )
+            responses = list_poll_responses(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+                projection_owner=projection_owner,
+            )
+        except PollError as exc:
+            raise PollCapabilityError(str(exc)) from exc
+        return tuple(_response_ref(response) for response in responses)
+
+    def get_response(
+        self,
+        session: object,
+        *,
+        tenant_id: str,
+        poll_id: str,
+        respondent_ids: Sequence[str],
+        invitation_id: str | None = None,
+    ) -> PollResponseRef | None:
+        try:
+            projection_owner = _stored_owner(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+            )
+            response = get_poll_response_for_respondents(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+                respondent_ids=tuple(respondent_ids),
+                invitation_id=invitation_id,
+                projection_owner=projection_owner,
+            )
+        except PollError as exc:
+            raise PollCapabilityError(str(exc)) from exc
+        return _response_ref(response) if response is not None else None
+
+    def retire_responses(
+        self,
+        session: object,
+        *,
+        tenant_id: str,
+        poll_id: str,
+        command: PollResponseRetirementCommand,
+    ) -> PollResponseRetirementRef:
+        try:
+            mutation_owner = _stored_owner(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+            )
+            responses, retired_at, retired_count, replayed = retire_poll_responses(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+                respondent_ids=command.respondent_ids,
+                invitation_id=command.invitation_id,
+                reason=command.reason,
+                idempotency_key=command.idempotency_key,
+                metadata=dict(command.metadata),
+                mutation_owner=mutation_owner,
+            )
+        except PollError as exc:
+            raise PollCapabilityError(str(exc)) from exc
+        return PollResponseRetirementRef(
+            response_ids=tuple(response.id for response in responses),
+            retired_at=response_datetime(retired_at),
+            newly_retired_count=retired_count,
+            replayed=replayed,
+        )
+
+    @staticmethod
+    def _transition(callback, session: object, *, tenant_id: str, poll_id: str) -> PollRef:
+        try:
+            mutation_owner = _stored_owner(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+            )
+            poll = callback(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+                mutation_owner=mutation_owner,
+            )
+        except PollError as exc:
+            raise PollCapabilityError(str(exc)) from exc
+        return _poll_ref(poll)

src/govoplan_poll/backend/db/__init__.py

@@ -1,5 +1,5 @@
 from __future__ import annotations
 
-from govoplan_poll.backend.db.models import Poll, PollInvitation, PollOption, PollResponse
+from govoplan_poll.backend.db.models import Poll, PollInvitation, PollLifecycleTransition, PollOption, PollResponse
 
-__all__ = ["Poll", "PollInvitation", "PollOption", "PollResponse"]
+__all__ = ["Poll", "PollInvitation", "PollLifecycleTransition", "PollOption", "PollResponse"]

src/govoplan_poll/backend/db/models.py

@@ -42,6 +42,11 @@ class Poll(Base, TimestampMixin):
     context_module: Mapped[str | None] = mapped_column(String(100), nullable=True, index=True)
     context_resource_type: Mapped[str | None] = mapped_column(String(100), nullable=True)
     context_resource_id: Mapped[str | None] = mapped_column(String(255), nullable=True, index=True)
+    participation_gateway_: Mapped[dict[str, Any] | None] = mapped_column(
+        "participation_gateway",
+        JSON,
+        nullable=True,
+    )
     workflow_state: Mapped[str | None] = mapped_column(String(100), nullable=True, index=True)
     workflow_steps: Mapped[list[dict[str, Any]]] = mapped_column(JSON, default=list, nullable=False)
     allow_anonymous: Mapped[bool] = mapped_column(Boolean, default=False, nullable=False)
@@ -53,6 +58,7 @@ class Poll(Base, TimestampMixin):
     closed_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
     decided_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
     decided_option_id: Mapped[str | None] = mapped_column(String(36), nullable=True, index=True)
+    archived_from_status: Mapped[str | None] = mapped_column(String(30), nullable=True)
     created_by_user_id: Mapped[str | None] = mapped_column(String(36), nullable=True, index=True)
     deleted_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True, index=True)
     metadata_: Mapped[dict[str, Any] | None] = mapped_column("metadata", JSON, nullable=True)
@@ -60,6 +66,11 @@ class Poll(Base, TimestampMixin):
     options: Mapped[list["PollOption"]] = relationship(back_populates="poll", cascade="all, delete-orphan", order_by="PollOption.position")
     responses: Mapped[list["PollResponse"]] = relationship(back_populates="poll", cascade="all, delete-orphan")
     invitations: Mapped[list["PollInvitation"]] = relationship(back_populates="poll", cascade="all, delete-orphan")
+    lifecycle_transitions: Mapped[list["PollLifecycleTransition"]] = relationship(
+        back_populates="poll",
+        cascade="all, delete-orphan",
+        order_by="PollLifecycleTransition.created_at",
+    )
 
 
 class PollOption(Base, TimestampMixin):
@@ -88,6 +99,18 @@ class PollResponse(Base, TimestampMixin):
     __table_args__ = (
         Index("ix_poll_responses_poll_submitted", "poll_id", "submitted_at"),
         Index("ix_poll_responses_poll_respondent", "poll_id", "respondent_id"),
+        Index(
+            "uq_poll_responses_active_respondent",
+            "poll_id",
+            "respondent_id",
+            unique=True,
+            sqlite_where=text(
+                "deleted_at IS NULL AND respondent_id IS NOT NULL"
+            ),
+            postgresql_where=text(
+                "deleted_at IS NULL AND respondent_id IS NOT NULL"
+            ),
+        ),
         Index("ix_poll_responses_tenant_poll", "tenant_id", "poll_id"),
     )
 
@@ -122,9 +145,80 @@ class PollInvitation(Base, TimestampMixin):
     expires_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True, index=True)
     revoked_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True, index=True)
     last_used_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
+    response_gateway_: Mapped[dict[str, Any] | None] = mapped_column("response_gateway", JSON, nullable=True)
+    participation_policy_: Mapped[dict[str, Any] | None] = mapped_column("participation_policy", JSON, nullable=True)
     metadata_: Mapped[dict[str, Any] | None] = mapped_column("metadata", JSON, nullable=True)
 
     poll: Mapped[Poll] = relationship(back_populates="invitations")
 
 
-__all__ = ["Poll", "PollInvitation", "PollOption", "PollResponse", "new_uuid"]
+class PollParticipationSubmission(Base, TimestampMixin):
+    __tablename__ = "poll_participation_submissions"
+    __table_args__ = (
+        UniqueConstraint(
+            "invitation_id",
+            "idempotency_key",
+            name="uq_poll_participation_submission_idempotency",
+        ),
+        Index(
+            "ix_poll_participation_submission_poll_created",
+            "tenant_id",
+            "poll_id",
+            "created_at",
+        ),
+    )
+
+    id: Mapped[str] = mapped_column(String(36), primary_key=True, default=new_uuid)
+    tenant_id: Mapped[str] = mapped_column(String(36), nullable=False, index=True)
+    poll_id: Mapped[str] = mapped_column(
+        ForeignKey("poll_polls.id", ondelete="CASCADE"),
+        nullable=False,
+        index=True,
+    )
+    invitation_id: Mapped[str] = mapped_column(
+        ForeignKey("poll_invitations.id", ondelete="CASCADE"),
+        nullable=False,
+        index=True,
+    )
+    response_id: Mapped[str] = mapped_column(
+        ForeignKey("poll_responses.id", ondelete="CASCADE"),
+        nullable=False,
+        index=True,
+    )
+    idempotency_key: Mapped[str] = mapped_column(String(255), nullable=False)
+    request_fingerprint: Mapped[str] = mapped_column(String(64), nullable=False)
+
+
+class PollLifecycleTransition(Base, TimestampMixin):
+    __tablename__ = "poll_lifecycle_transitions"
+    __table_args__ = (
+        UniqueConstraint("poll_id", "idempotency_key", name="uq_poll_lifecycle_transition_idempotency"),
+        Index("ix_poll_lifecycle_transition_poll_created", "poll_id", "created_at"),
+        Index("ix_poll_lifecycle_transition_tenant_poll", "tenant_id", "poll_id"),
+    )
+
+    id: Mapped[str] = mapped_column(String(36), primary_key=True, default=new_uuid)
+    tenant_id: Mapped[str] = mapped_column(String(36), nullable=False, index=True)
+    poll_id: Mapped[str] = mapped_column(ForeignKey("poll_polls.id", ondelete="CASCADE"), nullable=False, index=True)
+    action: Mapped[str] = mapped_column(String(30), nullable=False, index=True)
+    from_status: Mapped[str] = mapped_column(String(30), nullable=False)
+    to_status: Mapped[str] = mapped_column(String(30), nullable=False)
+    decision_option_id: Mapped[str | None] = mapped_column(String(36), nullable=True)
+    previous_decision_option_id: Mapped[str | None] = mapped_column(String(36), nullable=True)
+    idempotency_key: Mapped[str | None] = mapped_column(String(255), nullable=True)
+    actor_user_id: Mapped[str | None] = mapped_column(String(36), nullable=True, index=True)
+    actor_api_key_id: Mapped[str | None] = mapped_column(String(36), nullable=True, index=True)
+    metadata_: Mapped[dict[str, Any] | None] = mapped_column("metadata", JSON, nullable=True)
+
+    poll: Mapped[Poll] = relationship(back_populates="lifecycle_transitions")
+
+
+__all__ = [
+    "Poll",
+    "PollInvitation",
+    "PollLifecycleTransition",
+    "PollOption",
+    "PollParticipationSubmission",
+    "PollResponse",
+    "new_uuid",
+]

src/govoplan_poll/backend/manifest.py

@@ -13,12 +13,14 @@ from govoplan_core.core.modules import (
     PermissionDefinition,
     RoleTemplate,
 )
+from govoplan_core.core.poll import CAPABILITY_POLL_SCHEDULING
+from govoplan_core.core.poll_participation import CAPABILITY_POLL_PARTICIPATION_GATEWAY
 from govoplan_core.db.base import Base
 from govoplan_poll.backend.db import models as poll_models  # noqa: F401 - populate Poll ORM metadata
 
 MODULE_ID = "poll"
 MODULE_NAME = "Poll"
-MODULE_VERSION = "0.1.8"
+MODULE_VERSION = "0.1.11"
 READ_SCOPE = "poll:poll:read"
 WRITE_SCOPE = "poll:poll:write"
 ADMIN_SCOPE = "poll:poll:admin"
@@ -99,6 +101,17 @@ def _poll_router(_context: ModuleContext):
     return router
 
 
+def _poll_scheduling_provider(context: ModuleContext) -> object:
+    del context
+    from govoplan_poll.backend.capabilities import SqlPollSchedulingProvider
+
+    return SqlPollSchedulingProvider()
+
+
+def _poll_participation_gateway_provider(context: ModuleContext) -> object:
+    return _poll_scheduling_provider(context)
+
+
 manifest = ModuleManifest(
     id=MODULE_ID,
     name=MODULE_NAME,
@@ -107,16 +120,22 @@ manifest = ModuleManifest(
     optional_dependencies=("access", "calendar", "campaigns", "portal", "mail", "notifications", "forms_runtime"),
     optional_capabilities=(CAPABILITY_AUTH_PRINCIPAL_RESOLVER, CAPABILITY_AUTH_PERMISSION_EVALUATOR),
     provides_interfaces=(
-        ModuleInterfaceProvider(name="poll.option_selection", version="0.1.8"),
-        ModuleInterfaceProvider(name="poll.availability_matrix", version="0.1.8"),
-        ModuleInterfaceProvider(name="poll.response_collection", version="0.1.8"),
-        ModuleInterfaceProvider(name="poll.workflow_context", version="0.1.8"),
-        ModuleInterfaceProvider(name="poll.signed_participation", version="0.1.8"),
+        ModuleInterfaceProvider(name="poll.option_selection", version=MODULE_VERSION),
+        ModuleInterfaceProvider(name="poll.option_ordering", version=MODULE_VERSION),
+        ModuleInterfaceProvider(name="poll.availability_matrix", version=MODULE_VERSION),
+        ModuleInterfaceProvider(name="poll.response_collection", version=MODULE_VERSION),
+        ModuleInterfaceProvider(name="poll.workflow_context", version=MODULE_VERSION),
+        ModuleInterfaceProvider(name="poll.signed_participation", version=MODULE_VERSION),
+        ModuleInterfaceProvider(name="poll.governed_participation", version=MODULE_VERSION),
     ),
     permissions=PERMISSIONS,
     role_templates=ROLE_TEMPLATES,
     route_factory=_poll_router,
     tenant_summary_providers=(_tenant_summary,),
+    capability_factories={
+        CAPABILITY_POLL_SCHEDULING: _poll_scheduling_provider,
+        CAPABILITY_POLL_PARTICIPATION_GATEWAY: _poll_participation_gateway_provider,
+    },
     migration_spec=MigrationSpec(
         module_id=MODULE_ID,
         metadata=Base.metadata,
@@ -125,7 +144,9 @@ manifest = ModuleManifest(
         retirement_provider=drop_table_retirement_provider(
             poll_models.Poll,
             poll_models.PollInvitation,
+            poll_models.PollLifecycleTransition,
             poll_models.PollOption,
+            poll_models.PollParticipationSubmission,
             poll_models.PollResponse,
             label="Poll",
         ),
@@ -135,7 +156,9 @@ manifest = ModuleManifest(
         persistent_table_uninstall_guard(
             poll_models.Poll,
             poll_models.PollInvitation,
+            poll_models.PollLifecycleTransition,
             poll_models.PollOption,
+            poll_models.PollParticipationSubmission,
             poll_models.PollResponse,
             label="Poll",
         ),

src/govoplan_poll/backend/migrations/versions/3b4c5d6e7f8a_v019_poll_lifecycle.py

@@ -0,0 +1,67 @@
+"""v0.1.9 configurable Poll lifecycle history
+
+Revision ID: 3b4c5d6e7f8a
+Revises: 2a3b4c5d6e7f
+Create Date: 2026-07-20 00:00:00.000000
+"""
+from __future__ import annotations
+
+from alembic import op
+import sqlalchemy as sa
+
+
+revision = "3b4c5d6e7f8a"
+down_revision = "2a3b4c5d6e7f"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.add_column("poll_polls", sa.Column("archived_from_status", sa.String(length=30), nullable=True))
+    op.create_table(
+        "poll_lifecycle_transitions",
+        sa.Column("id", sa.String(length=36), nullable=False),
+        sa.Column("tenant_id", sa.String(length=36), nullable=False),
+        sa.Column("poll_id", sa.String(length=36), nullable=False),
+        sa.Column("action", sa.String(length=30), nullable=False),
+        sa.Column("from_status", sa.String(length=30), nullable=False),
+        sa.Column("to_status", sa.String(length=30), nullable=False),
+        sa.Column("decision_option_id", sa.String(length=36), nullable=True),
+        sa.Column("previous_decision_option_id", sa.String(length=36), nullable=True),
+        sa.Column("idempotency_key", sa.String(length=255), nullable=True),
+        sa.Column("actor_user_id", sa.String(length=36), nullable=True),
+        sa.Column("actor_api_key_id", sa.String(length=36), nullable=True),
+        sa.Column("metadata", sa.JSON(), nullable=True),
+        sa.Column("created_at", sa.DateTime(timezone=True), nullable=False),
+        sa.Column("updated_at", sa.DateTime(timezone=True), nullable=False),
+        sa.ForeignKeyConstraint(
+            ["poll_id"],
+            ["poll_polls.id"],
+            name=op.f("fk_poll_lifecycle_transitions_poll_id_poll_polls"),
+            ondelete="CASCADE",
+        ),
+        sa.PrimaryKeyConstraint("id", name=op.f("pk_poll_lifecycle_transitions")),
+        sa.UniqueConstraint("poll_id", "idempotency_key", name="uq_poll_lifecycle_transition_idempotency"),
+    )
+    op.create_index(op.f("ix_poll_lifecycle_transitions_action"), "poll_lifecycle_transitions", ["action"], unique=False)
+    op.create_index(op.f("ix_poll_lifecycle_transitions_actor_api_key_id"), "poll_lifecycle_transitions", ["actor_api_key_id"], unique=False)
+    op.create_index(op.f("ix_poll_lifecycle_transitions_actor_user_id"), "poll_lifecycle_transitions", ["actor_user_id"], unique=False)
+    op.create_index(op.f("ix_poll_lifecycle_transitions_poll_id"), "poll_lifecycle_transitions", ["poll_id"], unique=False)
+    op.create_index(op.f("ix_poll_lifecycle_transitions_tenant_id"), "poll_lifecycle_transitions", ["tenant_id"], unique=False)
+    op.create_index(
+        "ix_poll_lifecycle_transition_poll_created",
+        "poll_lifecycle_transitions",
+        ["poll_id", "created_at"],
+        unique=False,
+    )
+    op.create_index(
+        "ix_poll_lifecycle_transition_tenant_poll",
+        "poll_lifecycle_transitions",
+        ["tenant_id", "poll_id"],
+        unique=False,
+    )
+
+
+def downgrade() -> None:
+    op.drop_table("poll_lifecycle_transitions")
+    op.drop_column("poll_polls", "archived_from_status")

src/govoplan_poll/backend/migrations/versions/4c5d6e7f8a9b_v0110_governed_participation.py

@@ -0,0 +1,104 @@
+"""v0.1.10 governed signed participation
+
+Revision ID: 4c5d6e7f8a9b
+Revises: 3b4c5d6e7f8a
+Create Date: 2026-07-21 00:00:00.000000
+"""
+from __future__ import annotations
+
+from alembic import op
+import sqlalchemy as sa
+
+
+revision = "4c5d6e7f8a9b"
+down_revision = "3b4c5d6e7f8a"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.add_column(
+        "poll_invitations",
+        sa.Column("response_gateway", sa.JSON(), nullable=True),
+    )
+    op.add_column(
+        "poll_invitations",
+        sa.Column("participation_policy", sa.JSON(), nullable=True),
+    )
+    op.create_table(
+        "poll_participation_submissions",
+        sa.Column("id", sa.String(length=36), nullable=False),
+        sa.Column("tenant_id", sa.String(length=36), nullable=False),
+        sa.Column("poll_id", sa.String(length=36), nullable=False),
+        sa.Column("invitation_id", sa.String(length=36), nullable=False),
+        sa.Column("response_id", sa.String(length=36), nullable=False),
+        sa.Column("idempotency_key", sa.String(length=255), nullable=False),
+        sa.Column("request_fingerprint", sa.String(length=64), nullable=False),
+        sa.Column("created_at", sa.DateTime(timezone=True), nullable=False),
+        sa.Column("updated_at", sa.DateTime(timezone=True), nullable=False),
+        sa.ForeignKeyConstraint(
+            ["poll_id"],
+            ["poll_polls.id"],
+            name=op.f("fk_poll_participation_submissions_poll_id_poll_polls"),
+            ondelete="CASCADE",
+        ),
+        sa.ForeignKeyConstraint(
+            ["invitation_id"],
+            ["poll_invitations.id"],
+            name=op.f(
+                "fk_poll_participation_submissions_invitation_id_poll_invitations"
+            ),
+            ondelete="CASCADE",
+        ),
+        sa.ForeignKeyConstraint(
+            ["response_id"],
+            ["poll_responses.id"],
+            name=op.f("fk_poll_participation_submissions_response_id_poll_responses"),
+            ondelete="CASCADE",
+        ),
+        sa.PrimaryKeyConstraint(
+            "id",
+            name=op.f("pk_poll_participation_submissions"),
+        ),
+        sa.UniqueConstraint(
+            "invitation_id",
+            "idempotency_key",
+            name="uq_poll_participation_submission_idempotency",
+        ),
+    )
+    op.create_index(
+        op.f("ix_poll_participation_submissions_tenant_id"),
+        "poll_participation_submissions",
+        ["tenant_id"],
+        unique=False,
+    )
+    op.create_index(
+        op.f("ix_poll_participation_submissions_poll_id"),
+        "poll_participation_submissions",
+        ["poll_id"],
+        unique=False,
+    )
+    op.create_index(
+        op.f("ix_poll_participation_submissions_invitation_id"),
+        "poll_participation_submissions",
+        ["invitation_id"],
+        unique=False,
+    )
+    op.create_index(
+        op.f("ix_poll_participation_submissions_response_id"),
+        "poll_participation_submissions",
+        ["response_id"],
+        unique=False,
+    )
+    op.create_index(
+        "ix_poll_participation_submission_poll_created",
+        "poll_participation_submissions",
+        ["tenant_id", "poll_id", "created_at"],
+        unique=False,
+    )
+
+
+def downgrade() -> None:
+    op.drop_table("poll_participation_submissions")
+    op.drop_column("poll_invitations", "participation_policy")
+    op.drop_column("poll_invitations", "response_gateway")

src/govoplan_poll/backend/migrations/versions/5d6e7f8a9b0c_v0110_poll_participation_owner.py

@@ -0,0 +1,64 @@
+"""v0.1.10 durable Poll participation owner
+
+Revision ID: 5d6e7f8a9b0c
+Revises: 4c5d6e7f8a9b
+Create Date: 2026-07-21 00:00:01.000000
+"""
+from __future__ import annotations
+
+from alembic import op
+import sqlalchemy as sa
+
+
+revision = "5d6e7f8a9b0c"
+down_revision = "4c5d6e7f8a9b"
+branch_labels = None
+depends_on = None
+
+
+def _backfill_existing_governed_polls() -> None:
+    """Retain the owner of installations that already used revision 4c5."""
+
+    polls = sa.table(
+        "poll_polls",
+        sa.column("id", sa.String(length=36)),
+        sa.column("participation_gateway", sa.JSON()),
+    )
+    invitations = sa.table(
+        "poll_invitations",
+        sa.column("id", sa.String(length=36)),
+        sa.column("poll_id", sa.String(length=36)),
+        sa.column("response_gateway", sa.JSON()),
+    )
+    connection = op.get_bind()
+    rows = connection.execute(
+        sa.select(
+            invitations.c.poll_id,
+            invitations.c.response_gateway,
+        ).order_by(invitations.c.poll_id.asc(), invitations.c.id.asc())
+    ).mappings()
+    claimed_poll_ids: set[str] = set()
+    for row in rows:
+        poll_id = row["poll_id"]
+        gateway = row["response_gateway"]
+        if poll_id in claimed_poll_ids or not isinstance(gateway, dict):
+            continue
+        connection.execute(
+            polls.update()
+            .where(polls.c.id == poll_id)
+            .where(polls.c.participation_gateway.is_(None))
+            .values(participation_gateway=gateway)
+        )
+        claimed_poll_ids.add(poll_id)
+
+
+def upgrade() -> None:
+    op.add_column(
+        "poll_polls",
+        sa.Column("participation_gateway", sa.JSON(), nullable=True),
+    )
+    _backfill_existing_governed_polls()
+
+
+def downgrade() -> None:
+    op.drop_column("poll_polls", "participation_gateway")

src/govoplan_poll/backend/migrations/versions/6e7f8a9b0c1d_v0111_poll_response_uniqueness.py

@@ -0,0 +1,99 @@
+"""v0.1.11 active identified Poll response uniqueness
+
+Revision ID: 6e7f8a9b0c1d
+Revises: 5d6e7f8a9b0c
+Create Date: 2026-07-22 00:00:00.000000
+
+This migration deduplicates active identified responses before creating the
+partial unique index. Run it while Poll response writes are quiesced or while
+the platform maintenance lock is held. PostgreSQL additionally takes a table
+lock so an unexpected writer cannot enter between cleanup and index creation.
+"""
+from __future__ import annotations
+
+from alembic import op
+import sqlalchemy as sa
+
+
+revision = "6e7f8a9b0c1d"
+down_revision = "5d6e7f8a9b0c"
+branch_labels = None
+depends_on = None
+
+
+_INDEX_NAME = "uq_poll_responses_active_respondent"
+_ACTIVE_IDENTIFIED_PREDICATE = (
+    "deleted_at IS NULL AND respondent_id IS NOT NULL"
+)
+
+
+def _tombstone_duplicate_active_responses() -> None:
+    responses = sa.table(
+        "poll_responses",
+        sa.column("id", sa.String(length=36)),
+        sa.column("poll_id", sa.String(length=36)),
+        sa.column("respondent_id", sa.String(length=255)),
+        sa.column("submitted_at", sa.DateTime(timezone=True)),
+        sa.column("deleted_at", sa.DateTime(timezone=True)),
+        sa.column("updated_at", sa.DateTime(timezone=True)),
+    )
+    ranked = (
+        sa.select(
+            responses.c.id.label("id"),
+            sa.func.row_number()
+            .over(
+                partition_by=(
+                    responses.c.poll_id,
+                    responses.c.respondent_id,
+                ),
+                order_by=(
+                    responses.c.submitted_at.desc(),
+                    responses.c.id.desc(),
+                ),
+            )
+            .label("response_rank"),
+        )
+        .where(
+            responses.c.deleted_at.is_(None),
+            responses.c.respondent_id.is_not(None),
+        )
+        .subquery("ranked_active_poll_responses")
+    )
+    duplicate_ids = sa.select(ranked.c.id).where(ranked.c.response_rank > 1)
+    migration_timestamp = sa.func.current_timestamp()
+    op.get_bind().execute(
+        responses.update()
+        .where(
+            responses.c.id.in_(duplicate_ids),
+            responses.c.deleted_at.is_(None),
+        )
+        .values(
+            deleted_at=migration_timestamp,
+            updated_at=migration_timestamp,
+        )
+    )
+
+
+def upgrade() -> None:
+    connection = op.get_bind()
+    if connection.dialect.name == "postgresql":
+        connection.execute(
+            sa.text(
+                "LOCK TABLE poll_responses IN SHARE ROW EXCLUSIVE MODE"
+            )
+        )
+    _tombstone_duplicate_active_responses()
+    op.create_index(
+        _INDEX_NAME,
+        "poll_responses",
+        ["poll_id", "respondent_id"],
+        unique=True,
+        sqlite_where=sa.text(_ACTIVE_IDENTIFIED_PREDICATE),
+        postgresql_where=sa.text(_ACTIVE_IDENTIFIED_PREDICATE),
+    )
+
+
+def downgrade() -> None:
+    # Deduplicated rows remain tombstoned: a downgrade must not silently revive
+    # responses that were no longer part of the active result set.
+    op.drop_index(_INDEX_NAME, table_name="poll_responses")

src/govoplan_poll/backend/participation.py

@@ -0,0 +1,43 @@
+"""Backward-compatible governed-participation contract imports.
+
+The provider contract belongs to Core so consumers can resolve Poll through
+the platform capability registry without importing Poll implementation
+internals.  This module intentionally preserves the original public import
+path for existing Poll integrations.
+"""
+
+from govoplan_core.core.poll_participation import (
+    ANONYMOUS_PASSWORD_REQUIREMENT,
+    CAPABILITY_POLL_PARTICIPATION_GATEWAY,
+    PARTICIPATION_POLICY_VERSION,
+    PollGovernedInvitationCommand,
+    PollGovernedResponseCommand,
+    PollGovernedResponseRef,
+    PollInvitationExpiryRef,
+    PollInvitationRevocationRef,
+    PollOptionMutationRef,
+    PollParticipationContextRef,
+    PollParticipationGatewayProvider,
+    PollParticipationPolicy,
+    PollResponseGatewayRef,
+    participation_token_fingerprint,
+    poll_participation_gateway_provider,
+)
+
+__all__ = [
+    "ANONYMOUS_PASSWORD_REQUIREMENT",
+    "CAPABILITY_POLL_PARTICIPATION_GATEWAY",
+    "PARTICIPATION_POLICY_VERSION",
+    "PollGovernedInvitationCommand",
+    "PollGovernedResponseCommand",
+    "PollGovernedResponseRef",
+    "PollInvitationExpiryRef",
+    "PollInvitationRevocationRef",
+    "PollOptionMutationRef",
+    "PollParticipationContextRef",
+    "PollParticipationGatewayProvider",
+    "PollParticipationPolicy",
+    "PollResponseGatewayRef",
+    "participation_token_fingerprint",
+    "poll_participation_gateway_provider",
+]

src/govoplan_poll/backend/participation_service.py

@@ -0,0 +1,739 @@
+from __future__ import annotations
+
+import hashlib
+import json
+from collections.abc import Mapping
+from datetime import datetime
+from typing import Any
+
+from pydantic import ValidationError
+from sqlalchemy.orm import Session
+
+from govoplan_poll.backend.db.models import (
+    Poll,
+    PollInvitation,
+    PollParticipationSubmission,
+    PollResponse,
+)
+from govoplan_poll.backend.participation import (
+    ANONYMOUS_PASSWORD_REQUIREMENT,
+    PollGovernedResponseCommand,
+    PollParticipationPolicy,
+    PollResponseGatewayRef,
+)
+from govoplan_poll.backend.schemas import (
+    PollAnswerInput,
+    PollParticipationPolicyInput,
+    PollResponseGatewayInput,
+    PollSubmitResponseRequest,
+)
+from govoplan_poll.backend.service import (
+    PollError,
+    _assert_governed_invitation_gateway_allowed,
+    _assert_poll_accepts_responses,
+    _existing_response,
+    _insert_or_reconcile_identified_response,
+    _lock_poll_for_response,
+    _now,
+    _update_existing_response,
+    assert_no_sensitive_participation_metadata,
+    get_poll_invitation_by_token,
+    normalize_response_answers,
+    response_datetime,
+)
+
+
+GENERIC_PARTICIPATION_ERROR = "Poll invitation not found"
+MAX_COMMENT_LENGTH = 4_000
+
+
+def response_gateway_payload(gateway: PollResponseGatewayRef) -> dict[str, str]:
+    try:
+        return PollResponseGatewayInput(
+            module_id=gateway.module_id,
+            resource_type=gateway.resource_type,
+            resource_id=gateway.resource_id,
+        ).model_dump(mode="json")
+    except ValidationError as exc:
+        raise PollError("Invalid participation response gateway") from exc
+
+
+def participation_policy_payload(policy: PollParticipationPolicy) -> dict[str, Any]:
+    try:
+        return PollParticipationPolicyInput(
+            version=policy.version,
+            single_choice=policy.single_choice,
+            allow_maybe=policy.allow_maybe,
+            max_participants_per_option=policy.max_participants_per_option,
+            allow_comments=policy.allow_comments,
+            participant_email_required=policy.participant_email_required,
+            anonymous_password_required=policy.anonymous_password_required,
+        ).model_dump(mode="json")
+    except ValidationError as exc:
+        raise PollError("Invalid participation policy") from exc
+
+
+def response_gateway_ref(value: Mapping[str, Any] | None) -> PollResponseGatewayRef:
+    try:
+        parsed = PollResponseGatewayInput.model_validate(value)
+    except ValidationError as exc:
+        raise PollError(GENERIC_PARTICIPATION_ERROR) from exc
+    return PollResponseGatewayRef(
+        module_id=parsed.module_id,
+        resource_type=parsed.resource_type,
+        resource_id=parsed.resource_id,
+    )
+
+
+def participation_policy_ref(value: Mapping[str, Any] | None) -> PollParticipationPolicy:
+    try:
+        parsed = PollParticipationPolicyInput.model_validate(value)
+    except ValidationError as exc:
+        raise PollError(GENERIC_PARTICIPATION_ERROR) from exc
+    return PollParticipationPolicy(
+        version=parsed.version,
+        single_choice=parsed.single_choice,
+        allow_maybe=parsed.allow_maybe,
+        max_participants_per_option=parsed.max_participants_per_option,
+        allow_comments=parsed.allow_comments,
+        participant_email_required=parsed.participant_email_required,
+        anonymous_password_required=parsed.anonymous_password_required,
+    )
+
+
+def governed_invitation(
+    session: Session,
+    *,
+    token: str,
+    gateway: PollResponseGatewayRef,
+    lock: bool = False,
+) -> PollInvitation:
+    """Resolve a gateway-bound token without revealing which check failed."""
+
+    try:
+        invitation = get_poll_invitation_by_token(session, token=token)
+        _assert_governed_invitation(invitation, gateway=gateway)
+        if lock:
+            invitation = (
+                session.query(PollInvitation)
+                .filter(PollInvitation.id == invitation.id)
+                .populate_existing()
+                .with_for_update()
+                .one_or_none()
+            )
+            _assert_governed_invitation(invitation, gateway=gateway)
+    except (PollError, ValidationError) as exc:
+        raise PollError(GENERIC_PARTICIPATION_ERROR) from exc
+    if invitation is None:
+        raise PollError(GENERIC_PARTICIPATION_ERROR)
+    return invitation
+
+
+def _assert_governed_invitation(
+    invitation: PollInvitation | None,
+    *,
+    gateway: PollResponseGatewayRef,
+    authenticated_respondent_id: str | None = None,
+) -> None:
+    if invitation is None or invitation.poll.deleted_at is not None:
+        raise PollError(GENERIC_PARTICIPATION_ERROR)
+    if invitation.revoked_at is not None:
+        raise PollError(GENERIC_PARTICIPATION_ERROR)
+    if (
+        invitation.expires_at is not None
+        and response_datetime(invitation.expires_at) <= _now()
+    ):
+        raise PollError(GENERIC_PARTICIPATION_ERROR)
+    _assert_governed_invitation_gateway_allowed(
+        poll=invitation.poll,
+        gateway=response_gateway_payload(gateway),
+    )
+    if response_gateway_ref(invitation.response_gateway_) != gateway:
+        raise PollError(GENERIC_PARTICIPATION_ERROR)
+    participation_policy_ref(invitation.participation_policy_)
+    if authenticated_respondent_id is not None and (
+        invitation.respondent_id is not None
+        and invitation.respondent_id != authenticated_respondent_id
+    ):
+        raise PollError(GENERIC_PARTICIPATION_ERROR)
+
+
+def governed_invitation_by_id(
+    session: Session,
+    *,
+    tenant_id: str,
+    poll_id: str,
+    invitation_id: str,
+    gateway: PollResponseGatewayRef,
+    respondent_id: str,
+    lock: bool = False,
+) -> PollInvitation:
+    """Resolve an active governed invitation for one authenticated identity."""
+
+    if not respondent_id:
+        raise PollError(GENERIC_PARTICIPATION_ERROR)
+    try:
+        query = session.query(PollInvitation).filter(
+            PollInvitation.tenant_id == tenant_id,
+            PollInvitation.poll_id == poll_id,
+            PollInvitation.id == invitation_id,
+        )
+        if lock:
+            query = query.populate_existing().with_for_update()
+        invitation = query.one_or_none()
+        _assert_governed_invitation(
+            invitation,
+            gateway=gateway,
+            authenticated_respondent_id=respondent_id,
+        )
+    except PollError as exc:
+        raise PollError(GENERIC_PARTICIPATION_ERROR) from exc
+    if invitation is None:
+        raise PollError(GENERIC_PARTICIPATION_ERROR)
+    return invitation
+
+
+def update_governed_invitation_expiry(
+    session: Session,
+    *,
+    tenant_id: str,
+    poll_id: str,
+    invitation_id: str,
+    gateway: PollResponseGatewayRef,
+    expires_at: datetime | None,
+) -> tuple[PollInvitation, bool]:
+    """Update expiry without rotating the bearer token or reviving revocation."""
+
+    poll = _lock_poll_for_response(
+        session,
+        tenant_id=tenant_id,
+        poll_id=poll_id,
+    )
+    invitation = (
+        session.query(PollInvitation)
+        .filter(
+            PollInvitation.tenant_id == tenant_id,
+            PollInvitation.poll_id == poll.id,
+            PollInvitation.id == invitation_id,
+        )
+        .populate_existing()
+        .with_for_update()
+        .one_or_none()
+    )
+    try:
+        if invitation is None or invitation.revoked_at is not None:
+            raise PollError(GENERIC_PARTICIPATION_ERROR)
+        _assert_governed_invitation_gateway_allowed(
+            poll=poll,
+            gateway=response_gateway_payload(gateway),
+        )
+        if response_gateway_ref(invitation.response_gateway_) != gateway:
+            raise PollError(GENERIC_PARTICIPATION_ERROR)
+        participation_policy_ref(invitation.participation_policy_)
+    except (PollError, ValidationError) as exc:
+        raise PollError(GENERIC_PARTICIPATION_ERROR) from exc
+
+    normalized_expiry = response_datetime(expires_at)
+    replayed = response_datetime(invitation.expires_at) == normalized_expiry
+    if not replayed:
+        invitation.expires_at = normalized_expiry
+        session.flush()
+    return invitation, replayed
+
+
+def _normalize_email(value: str | None) -> str | None:
+    if value is None:
+        return None
+    normalized = value.strip().casefold()
+    if not normalized:
+        return None
+    if (
+        normalized.count("@") != 1
+        or any(character.isspace() for character in normalized)
+        or not all(normalized.split("@", 1))
+    ):
+        raise PollError("Participant email is invalid")
+    return normalized
+
+
+def _canonical_respondent_id(
+    invitation: PollInvitation,
+    *,
+    respondent_id: str | None,
+    participant_email: str | None,
+    participant_is_authenticated: bool,
+) -> str:
+    if invitation.respondent_id:
+        return invitation.respondent_id
+    if participant_is_authenticated and respondent_id:
+        return respondent_id
+    if participant_email and invitation.email is None:
+        email_fingerprint = hashlib.sha256(participant_email.encode("utf-8")).hexdigest()
+        return f"invitation:{invitation.id}:email:{email_fingerprint}"
+    return f"invitation:{invitation.id}"
+
+
+def _normalize_comment(value: str | None) -> str | None:
+    if value is None:
+        return None
+    normalized = value.strip()
+    if len(normalized) > MAX_COMMENT_LENGTH:
+        raise PollError(f"Participation comments cannot exceed {MAX_COMMENT_LENGTH} characters")
+    return normalized or None
+
+
+def _answer_reserves_capacity(poll: Poll, answer: Mapping[str, Any]) -> bool:
+    if poll.kind == "availability":
+        return answer.get("value") == "available"
+    return True
+
+
+def _validate_gateway_rules(
+    *,
+    invitation: PollInvitation,
+    policy: PollParticipationPolicy,
+    command: PollGovernedResponseCommand,
+) -> tuple[str | None, str | None, list[PollAnswerInput]]:
+    normalized_email = _normalize_email(command.participant_email or invitation.email)
+    invitation_email = _normalize_email(invitation.email)
+    if invitation_email is not None and normalized_email != invitation_email:
+        raise PollError("Participant email does not match this invitation")
+    if (
+        not command.participant_is_authenticated
+        and policy.participant_email_required
+        and normalized_email is None
+    ):
+        raise PollError("Participant email is required")
+    if (
+        not command.participant_is_authenticated
+        and policy.anonymous_password_required
+        and ANONYMOUS_PASSWORD_REQUIREMENT not in command.verified_requirements
+    ):
+        raise PollError("Anonymous password verification is required")
+
+    comment = _normalize_comment(command.comment)
+    if comment is not None and not policy.allow_comments:
+        raise PollError("Comments are not enabled for this participation link")
+
+    answers = [
+        PollAnswerInput(
+            option_id=answer.option_id,
+            option_key=answer.option_key,
+            value=answer.value,
+            rank=answer.rank,
+        )
+        for answer in command.answers
+    ]
+    return normalized_email, comment, answers
+
+
+def _validate_normalized_gateway_answers(
+    *,
+    poll: Poll,
+    policy: PollParticipationPolicy,
+    normalized_answers: list[dict[str, Any]],
+) -> None:
+    """Enforce policy against Poll-resolved option identities and values."""
+
+    if not policy.allow_maybe and any(
+        answer.get("value") == "maybe" or answer.get("option_key") == "maybe"
+        for answer in normalized_answers
+    ):
+        raise PollError("Maybe responses are not enabled for this participation link")
+    selected_count = sum(
+        (
+            answer.get("value") != "unavailable"
+            if poll.kind == "availability"
+            else True
+        )
+        for answer in normalized_answers
+    )
+    if policy.single_choice and selected_count > 1:
+        raise PollError("Only one poll option may be selected")
+
+
+def _selected_capacity_option_ids(
+    poll: Poll,
+    normalized_answers: list[dict[str, Any]],
+) -> set[str]:
+    return {
+        str(answer["option_id"])
+        for answer in normalized_answers
+        if answer.get("option_id") and _answer_reserves_capacity(poll, answer)
+    }
+
+
+def _enforce_capacity(
+    session: Session,
+    *,
+    poll: Poll,
+    existing: PollResponse | None,
+    normalized_answers: list[dict[str, Any]],
+    limit: int | None,
+) -> None:
+    if limit is None:
+        return
+    selected = _selected_capacity_option_ids(poll, normalized_answers)
+    if not selected:
+        return
+    counts = dict.fromkeys(selected, 0)
+    responses = (
+        session.query(PollResponse)
+        .filter(
+            PollResponse.tenant_id == poll.tenant_id,
+            PollResponse.poll_id == poll.id,
+            PollResponse.deleted_at.is_(None),
+        )
+        .order_by(PollResponse.id.asc())
+        .all()
+    )
+    for response in responses:
+        if existing is not None and response.id == existing.id:
+            continue
+        for answer in response.answers or []:
+            if (
+                isinstance(answer, Mapping)
+                and answer.get("option_id") in counts
+                and _answer_reserves_capacity(poll, answer)
+            ):
+                counts[str(answer["option_id"])] += 1
+    full = {option_id for option_id, count in counts.items() if count >= limit}
+    if full:
+        raise PollError("Participant limit reached for one or more poll options")
+
+
+def _normalize_idempotency_key(value: str | None) -> str | None:
+    if value is None:
+        return None
+    normalized = value.strip()
+    if not normalized:
+        raise PollError("Idempotency key cannot be empty")
+    if len(normalized) > 255:
+        raise PollError("Idempotency key cannot be longer than 255 characters")
+    return normalized
+
+
+def _submission_fingerprint(
+    *,
+    gateway: PollResponseGatewayRef,
+    command: PollGovernedResponseCommand,
+    normalized_email: str | None,
+    comment: str | None,
+) -> str:
+    value = {
+        "gateway": response_gateway_payload(gateway),
+        "respondent_id": command.respondent_id,
+        "respondent_label": command.respondent_label,
+        "participant_email": normalized_email,
+        "participant_is_authenticated": command.participant_is_authenticated,
+        "answers": [
+            {
+                "option_id": answer.option_id,
+                "option_key": answer.option_key,
+                "value": answer.value,
+                "rank": answer.rank,
+            }
+            for answer in command.answers
+        ],
+        "comment": comment,
+        "verified_requirements": sorted(command.verified_requirements),
+        "metadata": dict(command.metadata),
+    }
+    encoded = json.dumps(
+        value,
+        sort_keys=True,
+        separators=(",", ":"),
+        ensure_ascii=False,
+        default=str,
+    ).encode("utf-8")
+    return hashlib.sha256(encoded).hexdigest()
+
+
+def _idempotent_submission(
+    session: Session,
+    *,
+    invitation_id: str,
+    idempotency_key: str | None,
+    request_fingerprint: str,
+) -> PollResponse | None:
+    if idempotency_key is None:
+        return None
+    submission = (
+        session.query(PollParticipationSubmission)
+        .filter(
+            PollParticipationSubmission.invitation_id == invitation_id,
+            PollParticipationSubmission.idempotency_key == idempotency_key,
+        )
+        .one_or_none()
+    )
+    if submission is None:
+        return None
+    if submission.request_fingerprint != request_fingerprint:
+        raise PollError("Idempotency key was already used for a different response")
+    response = (
+        session.query(PollResponse)
+        .filter(PollResponse.id == submission.response_id)
+        .one_or_none()
+    )
+    if response is None:
+        raise PollError("Idempotent response record is no longer available")
+    return response
+
+
+def submit_governed_poll_response(
+    session: Session,
+    *,
+    token: str,
+    gateway: PollResponseGatewayRef,
+    command: PollGovernedResponseCommand,
+) -> tuple[PollInvitation, PollResponse, bool]:
+    """Submit through a bound gateway and enforce its snapshot atomically."""
+
+    initial = governed_invitation(session, token=token, gateway=gateway)
+    poll = _lock_poll_for_response(
+        session,
+        tenant_id=initial.tenant_id,
+        poll_id=initial.poll_id,
+    )
+    invitation = governed_invitation(session, token=token, gateway=gateway, lock=True)
+    if invitation.poll_id != poll.id:
+        raise PollError(GENERIC_PARTICIPATION_ERROR)
+    return _submit_locked_governed_response(
+        session,
+        poll=poll,
+        invitation=invitation,
+        gateway=gateway,
+        command=command,
+    )
+
+
+def submit_authenticated_poll_response(
+    session: Session,
+    *,
+    tenant_id: str,
+    poll_id: str,
+    invitation_id: str,
+    gateway: PollResponseGatewayRef,
+    respondent_id: str,
+    command: PollGovernedResponseCommand,
+) -> tuple[PollInvitation, PollResponse, bool]:
+    """Submit by governed invitation id for one authenticated respondent."""
+
+    if (
+        not command.participant_is_authenticated
+        or not respondent_id
+        or command.respondent_id != respondent_id
+    ):
+        raise PollError(GENERIC_PARTICIPATION_ERROR)
+    initial = governed_invitation_by_id(
+        session,
+        tenant_id=tenant_id,
+        poll_id=poll_id,
+        invitation_id=invitation_id,
+        gateway=gateway,
+        respondent_id=respondent_id,
+    )
+    poll = _lock_poll_for_response(
+        session,
+        tenant_id=tenant_id,
+        poll_id=poll_id,
+    )
+    invitation = governed_invitation_by_id(
+        session,
+        tenant_id=tenant_id,
+        poll_id=poll_id,
+        invitation_id=invitation_id,
+        gateway=gateway,
+        respondent_id=respondent_id,
+        lock=True,
+    )
+    if initial.id != invitation.id or invitation.poll_id != poll.id:
+        raise PollError(GENERIC_PARTICIPATION_ERROR)
+    return _submit_locked_governed_response(
+        session,
+        poll=poll,
+        invitation=invitation,
+        gateway=gateway,
+        command=command,
+    )
+
+
+def _submit_locked_governed_response(
+    session: Session,
+    *,
+    poll: Poll,
+    invitation: PollInvitation,
+    gateway: PollResponseGatewayRef,
+    command: PollGovernedResponseCommand,
+) -> tuple[PollInvitation, PollResponse, bool]:
+    policy = participation_policy_ref(invitation.participation_policy_)
+    assert_no_sensitive_participation_metadata(command.metadata)
+    normalized_email, comment, answer_inputs = _validate_gateway_rules(
+        invitation=invitation,
+        policy=policy,
+        command=command,
+    )
+    respondent_id = _canonical_respondent_id(
+        invitation,
+        respondent_id=command.respondent_id,
+        participant_email=normalized_email,
+        participant_is_authenticated=command.participant_is_authenticated,
+    )
+    idempotency_key = _normalize_idempotency_key(command.idempotency_key)
+    request_fingerprint = _submission_fingerprint(
+        gateway=gateway,
+        command=command,
+        normalized_email=normalized_email,
+        comment=comment,
+    )
+    replay = _idempotent_submission(
+        session,
+        invitation_id=invitation.id,
+        idempotency_key=idempotency_key,
+        request_fingerprint=request_fingerprint,
+    )
+    if replay is not None:
+        return invitation, replay, True
+
+    _assert_poll_accepts_responses(poll)
+    payload = PollSubmitResponseRequest(
+        respondent_id=respondent_id,
+        respondent_label=(
+            command.respondent_label
+            or invitation.respondent_label
+            or invitation.email
+            or normalized_email
+        ),
+        answers=answer_inputs,
+        metadata={
+            key: value
+            for key, value in command.metadata.items()
+            if key not in {"invitation_id", "participant_email", "comment", "response_gateway"}
+        },
+    )
+    normalized_answers = normalize_response_answers(poll, payload)
+    _validate_normalized_gateway_answers(
+        poll=poll,
+        policy=policy,
+        normalized_answers=normalized_answers,
+    )
+    existing = _existing_response(session, poll=poll, respondent_id=respondent_id)
+    _enforce_capacity(
+        session,
+        poll=poll,
+        existing=existing,
+        normalized_answers=normalized_answers,
+        limit=policy.max_participants_per_option,
+    )
+    trusted_metadata = dict(payload.metadata)
+    trusted_metadata["invitation_id"] = invitation.id
+    trusted_metadata["response_gateway"] = response_gateway_payload(gateway)
+    if normalized_email is not None:
+        trusted_metadata["participant_email"] = normalized_email
+    if comment is not None:
+        trusted_metadata["comment"] = comment
+    now = _now()
+    if existing is not None:
+        response = _update_existing_response(
+            session,
+            poll=poll,
+            response=existing,
+            answers=normalized_answers,
+            respondent_label=payload.respondent_label,
+            submitted_at=now,
+            metadata=trusted_metadata,
+        )
+    else:
+        response, _reconciled = _insert_or_reconcile_identified_response(
+            session,
+            poll=poll,
+            respondent_id=respondent_id,
+            respondent_label=payload.respondent_label,
+            answers=normalized_answers,
+            submitted_at=now,
+            metadata=trusted_metadata,
+            conflict_validator=lambda winner: _enforce_capacity(
+                session,
+                poll=poll,
+                existing=winner,
+                normalized_answers=normalized_answers,
+                limit=policy.max_participants_per_option,
+            ),
+        )
+    if idempotency_key is not None:
+        session.add(
+            PollParticipationSubmission(
+                tenant_id=poll.tenant_id,
+                poll_id=poll.id,
+                invitation_id=invitation.id,
+                response_id=response.id,
+                idempotency_key=idempotency_key,
+                request_fingerprint=request_fingerprint,
+            )
+        )
+    invitation.last_used_at = response.submitted_at
+    session.flush()
+    return invitation, response, False
+
+
+def response_metadata(response: PollResponse) -> tuple[str | None, str | None]:
+    metadata = response.metadata_ or {}
+    email = metadata.get("participant_email")
+    comment = metadata.get("comment")
+    return (
+        email if isinstance(email, str) else None,
+        comment if isinstance(comment, str) else None,
+    )
+
+
+def response_for_invitation(
+    session: Session,
+    *,
+    invitation: PollInvitation,
+    respondent_id: str | None = None,
+    participant_email: str | None = None,
+) -> PollResponse | None:
+    normalized_email = _normalize_email(participant_email)
+    if invitation.respondent_id:
+        response_respondent_id = invitation.respondent_id
+    elif respondent_id:
+        response_respondent_id = respondent_id
+    elif invitation.email:
+        response_respondent_id = f"invitation:{invitation.id}"
+    elif normalized_email:
+        response_respondent_id = _canonical_respondent_id(
+            invitation,
+            respondent_id=None,
+            participant_email=normalized_email,
+            participant_is_authenticated=False,
+        )
+    else:
+        return None
+    return (
+        session.query(PollResponse)
+        .filter(
+            PollResponse.tenant_id == invitation.tenant_id,
+            PollResponse.poll_id == invitation.poll_id,
+            PollResponse.respondent_id == response_respondent_id,
+            PollResponse.deleted_at.is_(None),
+        )
+        .order_by(PollResponse.submitted_at.desc(), PollResponse.id.desc())
+        .first()
+    )
+
+
+__all__ = [
+    "GENERIC_PARTICIPATION_ERROR",
+    "MAX_COMMENT_LENGTH",
+    "governed_invitation",
+    "governed_invitation_by_id",
+    "participation_policy_payload",
+    "participation_policy_ref",
+    "response_for_invitation",
+    "response_gateway_payload",
+    "response_gateway_ref",
+    "response_metadata",
+    "submit_authenticated_poll_response",
+    "submit_governed_poll_response",
+    "update_governed_invitation_expiry",
+]

src/govoplan_poll/backend/router.py

@@ -1,17 +1,21 @@
 from __future__ import annotations
 
-from fastapi import APIRouter, Depends, HTTPException, Query, status
+from typing import Annotated
+
+from fastapi import APIRouter, Depends, Header, HTTPException, Query, status
 from sqlalchemy.orm import Session
 
 from govoplan_core.auth import ApiPrincipal, get_api_principal, has_scope
 from govoplan_core.db.session import get_session
-from govoplan_poll.backend.manifest import READ_SCOPE, RESPOND_SCOPE, WRITE_SCOPE
+from govoplan_poll.backend.manifest import ADMIN_SCOPE, READ_SCOPE, RESPOND_SCOPE, WRITE_SCOPE
 from govoplan_poll.backend.schemas import (
     PollCreateRequest,
     PollDecisionRequest,
     PollInvitationCreateRequest,
     PollInvitationListResponse,
     PollInvitationResponse,
+    PollLifecycleResponse,
+    PollLifecycleTransitionResponse,
     PollListResponse,
     PollResponse,
     PollResponseItem,
@@ -19,27 +23,35 @@ from govoplan_poll.backend.schemas import (
     PollResultSummaryResponse,
     PollStatusResponse,
     PollSubmitResponseRequest,
+    PollTransitionRequest,
+    PollTransitionAvailabilityResponse,
     PollUpdateRequest,
 )
 from govoplan_poll.backend.service import (
+    INVALID_POLL_OWNER,
+    OWNED_POLL_MUTATION_REQUIRED,
+    OWNED_POLL_PROJECTION_RESTRICTED,
+    POLL_OWNERSHIP_FIELDS_RESTRICTED,
     PollError,
-    close_poll,
+    assert_generic_poll_projection_allowed,
     create_poll_invitation,
     create_poll,
-    decide_poll,
     get_poll_by_invitation_token,
-    get_poll,
+    get_visible_poll,
     list_poll_responses,
     list_poll_invitations,
-    list_polls,
-    open_poll,
+    list_poll_lifecycle_transitions,
+    list_visible_polls,
     poll_invitation_response,
+    poll_lifecycle_transition_response,
     poll_response,
     poll_response_item,
     poll_result_summary_by_id,
+    require_visible_poll_results,
     revoke_poll_invitation,
     submit_poll_response,
     submit_poll_response_with_token,
+    transition_poll,
     update_poll,
 )
 
@@ -57,13 +69,109 @@ def _poll_http_error(exc: PollError) -> HTTPException:
         return HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail=str(exc))
     if str(exc) == "Poll invitation not found":
         return HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail=str(exc))
+    if str(exc) == "Poll results are not visible":
+        return HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail=str(exc))
+    if str(exc) == OWNED_POLL_PROJECTION_RESTRICTED:
+        return HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail=str(exc))
+    if str(exc) in {
+        INVALID_POLL_OWNER,
+        OWNED_POLL_MUTATION_REQUIRED,
+        POLL_OWNERSHIP_FIELDS_RESTRICTED,
+    }:
+        return HTTPException(status_code=status.HTTP_409_CONFLICT, detail=str(exc))
     return HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail=str(exc))
 
 
+def _public_participation_http_error(exc: PollError) -> HTTPException:
+    """Keep invalid, revoked, expired, and governed links indistinguishable."""
+
+    if str(exc).startswith("Poll invitation"):
+        return HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Poll invitation not found",
+        )
+    return _poll_http_error(exc)
+
+
 def _poll_response(poll) -> PollResponse:
     return PollResponse.model_validate(poll_response(poll))
 
 
+def _transition_status_response(result) -> PollStatusResponse:
+    return PollStatusResponse(
+        poll=_poll_response(result.poll),
+        transition=(
+            PollLifecycleTransitionResponse.model_validate(
+                poll_lifecycle_transition_response(result.transition)
+            )
+            if result.transition is not None
+            else None
+        ),
+        replayed=result.replayed,
+    )
+
+
+def _apply_transition(
+    session: Session,
+    principal: ApiPrincipal,
+    *,
+    poll_id: str,
+    action: str,
+    option_id: str | None = None,
+    option_key: str | None = None,
+    idempotency_key: str | None = None,
+) -> PollStatusResponse:
+    try:
+        result = transition_poll(
+            session,
+            tenant_id=principal.tenant_id,
+            poll_id=poll_id,
+            action=action,
+            option_id=option_id,
+            option_key=option_key,
+            idempotency_key=idempotency_key,
+            actor_user_id=getattr(principal.user, "id", None),
+            actor_api_key_id=getattr(principal.api_key, "id", None) if principal.api_key else None,
+        )
+    except PollError as exc:
+        raise _poll_http_error(exc) from exc
+    response = _transition_status_response(result)
+    session.commit()
+    return response
+
+
+def _principal_actor_ids(principal: ApiPrincipal) -> tuple[str, ...]:
+    candidates = (
+        principal.account_id,
+        principal.membership_id,
+        getattr(principal.user, "id", None),
+        principal.identity_id,
+        principal.principal.service_account_id,
+    )
+    return tuple(dict.fromkeys(str(value) for value in candidates if value))
+
+
+def _can_manage_polls(principal: ApiPrincipal) -> bool:
+    return has_scope(principal, WRITE_SCOPE) or has_scope(principal, ADMIN_SCOPE)
+
+
+def _can_view_sensitive_poll_data(principal: ApiPrincipal, poll: object) -> bool:
+    return _can_manage_polls(principal) or getattr(poll, "created_by_user_id", None) in _principal_actor_ids(principal)
+
+
+def _require_sensitive_poll_data_access(principal: ApiPrincipal, poll: object) -> None:
+    if not _can_view_sensitive_poll_data(principal, poll):
+        raise HTTPException(
+            status_code=status.HTTP_403_FORBIDDEN,
+            detail="Poll respondent and invitation data is restricted to poll organizers",
+        )
+
+
+def _require_sensitive_poll_data_scope(principal: ApiPrincipal) -> None:
+    if not (has_scope(principal, READ_SCOPE) or _can_manage_polls(principal)):
+        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail=f"Missing scope: {READ_SCOPE}")
+
+
 @router.get("/polls", response_model=PollListResponse)
 def api_list_polls(
     status_filter: str | None = Query(default=None, alias="status"),
@@ -72,7 +180,14 @@ def api_list_polls(
     principal: ApiPrincipal = Depends(get_api_principal),
 ) -> PollListResponse:
     _require_scope(principal, READ_SCOPE)
-    polls = list_polls(session, tenant_id=principal.tenant_id, status=status_filter, kind=kind)
+    polls = list_visible_polls(
+        session,
+        tenant_id=principal.tenant_id,
+        actor_ids=_principal_actor_ids(principal),
+        can_manage=_can_manage_polls(principal),
+        status=status_filter,
+        kind=kind,
+    )
     return PollListResponse(polls=[_poll_response(poll) for poll in polls])
 
 
@@ -87,7 +202,9 @@ def api_create_poll(
         poll = create_poll(session, tenant_id=principal.tenant_id, user_id=principal.account_id, payload=payload)
     except PollError as exc:
         raise _poll_http_error(exc) from exc
-    return _poll_response(poll)
+    response = _poll_response(poll)
+    session.commit()
+    return response
 
 
 @router.get("/polls/{poll_id}", response_model=PollResponse)
@@ -98,7 +215,15 @@ def api_get_poll(
 ) -> PollResponse:
     _require_scope(principal, READ_SCOPE)
     try:
-        return _poll_response(get_poll(session, tenant_id=principal.tenant_id, poll_id=poll_id))
+        return _poll_response(
+            get_visible_poll(
+                session,
+                tenant_id=principal.tenant_id,
+                poll_id=poll_id,
+                actor_ids=_principal_actor_ids(principal),
+                can_manage=_can_manage_polls(principal),
+            )
+        )
     except PollError as exc:
         raise _poll_http_error(exc) from exc
 
@@ -112,52 +237,172 @@ def api_update_poll(
 ) -> PollResponse:
     _require_scope(principal, WRITE_SCOPE)
     try:
-        return _poll_response(update_poll(session, tenant_id=principal.tenant_id, poll_id=poll_id, payload=payload))
+        poll = update_poll(session, tenant_id=principal.tenant_id, poll_id=poll_id, payload=payload)
     except PollError as exc:
         raise _poll_http_error(exc) from exc
+    response = _poll_response(poll)
+    session.commit()
+    return response
 
 
 @router.post("/polls/{poll_id}/open", response_model=PollStatusResponse)
 def api_open_poll(
     poll_id: str,
+    idempotency_key: Annotated[str | None, Header(alias="Idempotency-Key", max_length=255)] = None,
     session: Session = Depends(get_session),
     principal: ApiPrincipal = Depends(get_api_principal),
 ) -> PollStatusResponse:
     _require_scope(principal, WRITE_SCOPE)
-    try:
-        poll = open_poll(session, tenant_id=principal.tenant_id, poll_id=poll_id)
-    except PollError as exc:
-        raise _poll_http_error(exc) from exc
-    return PollStatusResponse(poll=_poll_response(poll))
+    return _apply_transition(
+        session,
+        principal,
+        poll_id=poll_id,
+        action="open",
+        idempotency_key=idempotency_key,
+    )
+
+
+@router.post("/polls/{poll_id}/draft", response_model=PollStatusResponse)
+def api_draft_poll(
+    poll_id: str,
+    idempotency_key: Annotated[str | None, Header(alias="Idempotency-Key", max_length=255)] = None,
+    session: Session = Depends(get_session),
+    principal: ApiPrincipal = Depends(get_api_principal),
+) -> PollStatusResponse:
+    _require_scope(principal, WRITE_SCOPE)
+    return _apply_transition(
+        session,
+        principal,
+        poll_id=poll_id,
+        action="draft",
+        idempotency_key=idempotency_key,
+    )
 
 
 @router.post("/polls/{poll_id}/close", response_model=PollStatusResponse)
 def api_close_poll(
     poll_id: str,
+    idempotency_key: Annotated[str | None, Header(alias="Idempotency-Key", max_length=255)] = None,
     session: Session = Depends(get_session),
     principal: ApiPrincipal = Depends(get_api_principal),
 ) -> PollStatusResponse:
     _require_scope(principal, WRITE_SCOPE)
-    try:
-        poll = close_poll(session, tenant_id=principal.tenant_id, poll_id=poll_id)
-    except PollError as exc:
-        raise _poll_http_error(exc) from exc
-    return PollStatusResponse(poll=_poll_response(poll))
+    return _apply_transition(
+        session,
+        principal,
+        poll_id=poll_id,
+        action="close",
+        idempotency_key=idempotency_key,
+    )
 
 
 @router.post("/polls/{poll_id}/decide", response_model=PollStatusResponse)
 def api_decide_poll(
     poll_id: str,
     payload: PollDecisionRequest,
+    idempotency_key: Annotated[str | None, Header(alias="Idempotency-Key", max_length=255)] = None,
     session: Session = Depends(get_session),
     principal: ApiPrincipal = Depends(get_api_principal),
 ) -> PollStatusResponse:
+    _require_scope(principal, WRITE_SCOPE)
+    return _apply_transition(
+        session,
+        principal,
+        poll_id=poll_id,
+        action="decide",
+        option_id=payload.option_id,
+        option_key=payload.option_key,
+        idempotency_key=idempotency_key,
+    )
+
+
+@router.post("/polls/{poll_id}/archive", response_model=PollStatusResponse)
+def api_archive_poll(
+    poll_id: str,
+    idempotency_key: Annotated[str | None, Header(alias="Idempotency-Key", max_length=255)] = None,
+    session: Session = Depends(get_session),
+    principal: ApiPrincipal = Depends(get_api_principal),
+) -> PollStatusResponse:
+    _require_scope(principal, WRITE_SCOPE)
+    return _apply_transition(
+        session,
+        principal,
+        poll_id=poll_id,
+        action="archive",
+        idempotency_key=idempotency_key,
+    )
+
+
+@router.post("/polls/{poll_id}/unarchive", response_model=PollStatusResponse)
+def api_unarchive_poll(
+    poll_id: str,
+    idempotency_key: Annotated[str | None, Header(alias="Idempotency-Key", max_length=255)] = None,
+    session: Session = Depends(get_session),
+    principal: ApiPrincipal = Depends(get_api_principal),
+) -> PollStatusResponse:
+    _require_scope(principal, WRITE_SCOPE)
+    return _apply_transition(
+        session,
+        principal,
+        poll_id=poll_id,
+        action="unarchive",
+        idempotency_key=idempotency_key,
+    )
+
+
+@router.post("/polls/{poll_id}/transitions", response_model=PollStatusResponse)
+def api_transition_poll(
+    poll_id: str,
+    payload: PollTransitionRequest,
+    idempotency_key: Annotated[str | None, Header(alias="Idempotency-Key", max_length=255)] = None,
+    session: Session = Depends(get_session),
+    principal: ApiPrincipal = Depends(get_api_principal),
+) -> PollStatusResponse:
+    _require_scope(principal, WRITE_SCOPE)
+    return _apply_transition(
+        session,
+        principal,
+        poll_id=poll_id,
+        action=payload.action,
+        option_id=payload.option_id,
+        option_key=payload.option_key,
+        idempotency_key=idempotency_key,
+    )
+
+
+@router.get("/polls/{poll_id}/transitions", response_model=PollLifecycleResponse)
+def api_poll_lifecycle(
+    poll_id: str,
+    session: Session = Depends(get_session),
+    principal: ApiPrincipal = Depends(get_api_principal),
+) -> PollLifecycleResponse:
     _require_scope(principal, WRITE_SCOPE)
     try:
-        poll = decide_poll(session, tenant_id=principal.tenant_id, poll_id=poll_id, payload=payload)
+        poll = get_visible_poll(
+            session,
+            tenant_id=principal.tenant_id,
+            poll_id=poll_id,
+            actor_ids=_principal_actor_ids(principal),
+            can_manage=True,
+        )
+        history = list_poll_lifecycle_transitions(
+            session,
+            tenant_id=principal.tenant_id,
+            poll_id=poll_id,
+        )
     except PollError as exc:
         raise _poll_http_error(exc) from exc
-    return PollStatusResponse(poll=_poll_response(poll))
+    projected = _poll_response(poll)
+    return PollLifecycleResponse(
+        poll_id=poll.id,
+        status=poll.status,
+        archived_from_status=poll.archived_from_status,
+        actions=[PollTransitionAvailabilityResponse.model_validate(item) for item in projected.lifecycle_actions],
+        history=[
+            PollLifecycleTransitionResponse.model_validate(poll_lifecycle_transition_response(item))
+            for item in history
+        ],
+    )
 
 
 @router.post("/polls/{poll_id}/responses", response_model=PollResponseItem, status_code=status.HTTP_201_CREATED)
@@ -169,10 +414,31 @@ def api_submit_poll_response(
 ) -> PollResponseItem:
     _require_scope(principal, RESPOND_SCOPE)
     try:
-        response = submit_poll_response(session, tenant_id=principal.tenant_id, poll_id=poll_id, payload=payload)
+        get_visible_poll(
+            session,
+            tenant_id=principal.tenant_id,
+            poll_id=poll_id,
+            actor_ids=_principal_actor_ids(principal),
+            can_manage=_can_manage_polls(principal),
+        )
+        actor_payload = payload.model_copy(
+            update={
+                "respondent_id": principal.account_id,
+                "respondent_label": principal.display_name or principal.email,
+                "metadata": {key: value for key, value in payload.metadata.items() if key != "invitation_id"},
+            }
+        )
+        response = submit_poll_response(
+            session,
+            tenant_id=principal.tenant_id,
+            poll_id=poll_id,
+            payload=actor_payload,
+        )
     except PollError as exc:
         raise _poll_http_error(exc) from exc
-    return PollResponseItem.model_validate(poll_response_item(response))
+    result = PollResponseItem.model_validate(poll_response_item(response))
+    session.commit()
+    return result
 
 
 @router.get("/polls/{poll_id}/responses", response_model=PollResponseListResponse)
@@ -181,8 +447,23 @@ def api_list_poll_responses(
     session: Session = Depends(get_session),
     principal: ApiPrincipal = Depends(get_api_principal),
 ) -> PollResponseListResponse:
-    _require_scope(principal, READ_SCOPE)
+    _require_sensitive_poll_data_scope(principal)
     try:
+        poll = get_visible_poll(
+            session,
+            tenant_id=principal.tenant_id,
+            poll_id=poll_id,
+            actor_ids=_principal_actor_ids(principal),
+            can_manage=_can_manage_polls(principal),
+        )
+        assert_generic_poll_projection_allowed(poll)
+        _require_sensitive_poll_data_access(principal, poll)
+        require_visible_poll_results(
+            session,
+            poll=poll,
+            actor_ids=_principal_actor_ids(principal),
+            can_manage=_can_manage_polls(principal),
+        )
         responses = list_poll_responses(session, tenant_id=principal.tenant_id, poll_id=poll_id)
     except PollError as exc:
         raise _poll_http_error(exc) from exc
@@ -197,6 +478,19 @@ def api_poll_summary(
 ) -> PollResultSummaryResponse:
     _require_scope(principal, READ_SCOPE)
     try:
+        poll = get_visible_poll(
+            session,
+            tenant_id=principal.tenant_id,
+            poll_id=poll_id,
+            actor_ids=_principal_actor_ids(principal),
+            can_manage=_can_manage_polls(principal),
+        )
+        require_visible_poll_results(
+            session,
+            poll=poll,
+            actor_ids=_principal_actor_ids(principal),
+            can_manage=_can_manage_polls(principal),
+        )
         return PollResultSummaryResponse.model_validate(poll_result_summary_by_id(session, tenant_id=principal.tenant_id, poll_id=poll_id))
     except PollError as exc:
         raise _poll_http_error(exc) from exc
@@ -214,7 +508,9 @@ def api_create_poll_invitation(
         invitation, token = create_poll_invitation(session, tenant_id=principal.tenant_id, poll_id=poll_id, payload=payload)
     except PollError as exc:
         raise _poll_http_error(exc) from exc
-    return PollInvitationResponse.model_validate(poll_invitation_response(invitation, token=token))
+    response = PollInvitationResponse.model_validate(poll_invitation_response(invitation, token=token))
+    session.commit()
+    return response
 
 
 @router.get("/polls/{poll_id}/invitations", response_model=PollInvitationListResponse)
@@ -223,8 +519,17 @@ def api_list_poll_invitations(
     session: Session = Depends(get_session),
     principal: ApiPrincipal = Depends(get_api_principal),
 ) -> PollInvitationListResponse:
-    _require_scope(principal, READ_SCOPE)
+    _require_sensitive_poll_data_scope(principal)
     try:
+        poll = get_visible_poll(
+            session,
+            tenant_id=principal.tenant_id,
+            poll_id=poll_id,
+            actor_ids=_principal_actor_ids(principal),
+            can_manage=_can_manage_polls(principal),
+        )
+        assert_generic_poll_projection_allowed(poll)
+        _require_sensitive_poll_data_access(principal, poll)
         invitations = list_poll_invitations(session, tenant_id=principal.tenant_id, poll_id=poll_id)
     except PollError as exc:
         raise _poll_http_error(exc) from exc
@@ -250,7 +555,9 @@ def api_revoke_poll_invitation(
         )
     except PollError as exc:
         raise _poll_http_error(exc) from exc
-    return PollInvitationResponse.model_validate(poll_invitation_response(invitation))
+    response = PollInvitationResponse.model_validate(poll_invitation_response(invitation))
+    session.commit()
+    return response
 
 
 @router.get("/public/{token}", response_model=PollResponse)
@@ -261,7 +568,7 @@ def api_get_public_poll(
     try:
         return _poll_response(get_poll_by_invitation_token(session, token=token))
     except PollError as exc:
-        raise _poll_http_error(exc) from exc
+        raise _public_participation_http_error(exc) from exc
 
 
 @router.post("/public/{token}/responses", response_model=PollResponseItem, status_code=status.HTTP_201_CREATED)
@@ -273,5 +580,7 @@ def api_submit_public_poll_response(
     try:
         response = submit_poll_response_with_token(session, token=token, payload=payload)
     except PollError as exc:
-        raise _poll_http_error(exc) from exc
-    return PollResponseItem.model_validate(poll_response_item(response))
+        raise _public_participation_http_error(exc) from exc
+    result = PollResponseItem.model_validate(poll_response_item(response))
+    session.commit()
+    return result

src/govoplan_poll/backend/schemas.py

@@ -8,6 +8,8 @@ from pydantic import BaseModel, ConfigDict, Field, model_validator
 
 PollKind = Literal["single_choice", "multiple_choice", "yes_no", "yes_no_maybe", "ranked_choice", "availability"]
 PollStatus = Literal["draft", "open", "closed", "decided", "archived"]
+PollInitialStatus = Literal["draft", "open"]
+PollTransitionAction = Literal["open", "draft", "close", "decide", "archive", "unarchive"]
 PollVisibility = Literal["private", "tenant", "public", "unlisted"]
 PollResultVisibility = Literal["organizer", "after_response", "after_close", "public"]
 AvailabilityValue = Literal["available", "maybe", "unavailable"]
@@ -30,7 +32,7 @@ class PollCreateRequest(BaseModel):
     slug: str | None = Field(default=None, max_length=120)
     description: str | None = None
     kind: PollKind = "single_choice"
-    status: PollStatus = "draft"
+    status: PollInitialStatus = "draft"
     visibility: PollVisibility = "private"
     result_visibility: PollResultVisibility = "after_close"
     context_module: str | None = Field(default=None, max_length=100)
@@ -85,6 +87,13 @@ class PollOptionResponse(BaseModel):
     metadata: dict[str, Any] = Field(default_factory=dict)
 
 
+class PollTransitionAvailabilityResponse(BaseModel):
+    action: PollTransitionAction
+    target_status: PollStatus | None = None
+    available: bool
+    reason: str | None = None
+
+
 class PollResponseItem(BaseModel):
     id: str
     respondent_id: str | None = None
@@ -120,11 +129,13 @@ class PollResponse(BaseModel):
     closed_at: datetime | None = None
     decided_at: datetime | None = None
     decided_option_id: str | None = None
+    archived_from_status: str | None = None
     created_by_user_id: str | None = None
     created_at: datetime
     updated_at: datetime
     metadata: dict[str, Any] = Field(default_factory=dict)
     options: list[PollOptionResponse] = Field(default_factory=list)
+    lifecycle_actions: list[PollTransitionAvailabilityResponse] = Field(default_factory=list)
 
 
 class PollListResponse(BaseModel):
@@ -175,14 +186,66 @@ class PollDecisionRequest(BaseModel):
     option_key: str | None = None
 
 
+class PollTransitionRequest(BaseModel):
+    model_config = ConfigDict(extra="forbid")
+
+    action: PollTransitionAction
+    option_id: str | None = None
+    option_key: str | None = None
+
+
+class PollLifecycleTransitionResponse(BaseModel):
+    id: str
+    action: PollTransitionAction
+    from_status: PollStatus
+    to_status: PollStatus
+    decision_option_id: str | None = None
+    previous_decision_option_id: str | None = None
+    idempotency_key: str | None = None
+    actor_user_id: str | None = None
+    actor_api_key_id: str | None = None
+    created_at: datetime
+    metadata: dict[str, Any] = Field(default_factory=dict)
+
+
 class PollStatusResponse(BaseModel):
     poll: PollResponse
+    transition: PollLifecycleTransitionResponse | None = None
+    replayed: bool = False
+
+
+class PollLifecycleResponse(BaseModel):
+    poll_id: str
+    status: PollStatus
+    archived_from_status: str | None = None
+    actions: list[PollTransitionAvailabilityResponse] = Field(default_factory=list)
+    history: list[PollLifecycleTransitionResponse] = Field(default_factory=list)
 
 
 class PollResponseListResponse(BaseModel):
     responses: list[PollResponseItem] = Field(default_factory=list)
 
 
+class PollResponseGatewayInput(BaseModel):
+    model_config = ConfigDict(extra="forbid")
+
+    module_id: str = Field(min_length=1, max_length=100)
+    resource_type: str = Field(min_length=1, max_length=100)
+    resource_id: str = Field(min_length=1, max_length=255)
+
+
+class PollParticipationPolicyInput(BaseModel):
+    model_config = ConfigDict(extra="forbid")
+
+    version: Literal[1] = 1
+    single_choice: bool = False
+    allow_maybe: bool = True
+    max_participants_per_option: int | None = Field(default=None, ge=1)
+    allow_comments: bool = False
+    participant_email_required: bool = False
+    anonymous_password_required: bool = False
+
+
 class PollInvitationCreateRequest(BaseModel):
     model_config = ConfigDict(extra="forbid")
 
@@ -190,8 +253,18 @@ class PollInvitationCreateRequest(BaseModel):
     respondent_label: str | None = Field(default=None, max_length=500)
     email: str | None = Field(default=None, max_length=320)
     expires_at: datetime | None = None
+    response_gateway: PollResponseGatewayInput | None = None
+    participation_policy: PollParticipationPolicyInput | None = None
     metadata: dict[str, Any] = Field(default_factory=dict)
 
+    @model_validator(mode="after")
+    def validate_governed_participation(self) -> "PollInvitationCreateRequest":
+        if (self.response_gateway is None) != (self.participation_policy is None):
+            raise ValueError(
+                "response_gateway and participation_policy must be configured together"
+            )
+        return self
+
 
 class PollInvitationResponse(BaseModel):
     id: str
@@ -205,6 +278,8 @@ class PollInvitationResponse(BaseModel):
     last_used_at: datetime | None = None
     created_at: datetime
     updated_at: datetime
+    response_gateway: PollResponseGatewayInput | None = None
+    participation_policy: PollParticipationPolicyInput | None = None
     metadata: dict[str, Any] = Field(default_factory=dict)
 
 

src/govoplan_poll/backend/transitions.py

@@ -0,0 +1,197 @@
+from __future__ import annotations
+
+from dataclasses import dataclass
+from types import MappingProxyType
+from typing import Mapping
+
+
+POLL_STATUSES = frozenset({"draft", "open", "closed", "decided", "archived"})
+POLL_TRANSITION_ACTIONS = ("open", "draft", "close", "decide", "archive", "unarchive")
+
+
+@dataclass(frozen=True)
+class PollTransitionRule:
+    """One configurable lifecycle action.
+
+    Archive restoration is deliberately represented as a dynamic target. The
+    engine remains a pure policy component; persistence and domain side effects
+    stay in the Poll service.
+    """
+
+    action: str
+    source_statuses: frozenset[str]
+    target_status: str | None
+    restore_archived_status: bool = False
+    missing_restore_target_status: str | None = None
+
+
+@dataclass(frozen=True)
+class PollTransitionPlan:
+    action: str
+    from_status: str
+    to_status: str
+
+
+@dataclass(frozen=True)
+class PollTransitionAvailability:
+    action: str
+    target_status: str | None
+    available: bool
+    reason: str | None = None
+
+
+class PollTransitionPolicy:
+    """Validated, replaceable configuration for a Poll lifecycle."""
+
+    def __init__(self, rules: Mapping[str, PollTransitionRule]) -> None:
+        normalized = dict(rules)
+        if set(normalized) != set(POLL_TRANSITION_ACTIONS):
+            missing = sorted(set(POLL_TRANSITION_ACTIONS) - set(normalized))
+            extra = sorted(set(normalized) - set(POLL_TRANSITION_ACTIONS))
+            raise ValueError(f"Poll transition policy has missing actions {missing} and extra actions {extra}")
+        for action, rule in normalized.items():
+            if rule.action != action:
+                raise ValueError(f"Poll transition rule key {action!r} does not match action {rule.action!r}")
+            if not rule.source_statuses <= POLL_STATUSES:
+                raise ValueError(f"Poll transition rule {action!r} has unknown source statuses")
+            if rule.restore_archived_status:
+                if rule.target_status is not None:
+                    raise ValueError(f"Restoring transition {action!r} cannot have a fixed target")
+                if rule.missing_restore_target_status not in (POLL_STATUSES - {"archived"}) | {None}:
+                    raise ValueError(f"Restoring transition {action!r} has an invalid missing-origin target")
+            elif rule.target_status not in POLL_STATUSES:
+                raise ValueError(f"Poll transition rule {action!r} has an unknown target status")
+            elif rule.missing_restore_target_status is not None:
+                raise ValueError(f"Non-restoring transition {action!r} cannot have a missing-origin target")
+        self._rules = MappingProxyType(normalized)
+
+    @property
+    def rules(self) -> Mapping[str, PollTransitionRule]:
+        return self._rules
+
+
+DEFAULT_POLL_TRANSITION_POLICY = PollTransitionPolicy(
+    {
+        "open": PollTransitionRule(
+            action="open",
+            source_statuses=frozenset({"draft", "closed", "decided"}),
+            target_status="open",
+        ),
+        "draft": PollTransitionRule(
+            action="draft",
+            source_statuses=frozenset({"open"}),
+            target_status="draft",
+        ),
+        "close": PollTransitionRule(
+            action="close",
+            source_statuses=frozenset({"open"}),
+            target_status="closed",
+        ),
+        "decide": PollTransitionRule(
+            action="decide",
+            source_statuses=frozenset({"closed", "decided"}),
+            target_status="decided",
+        ),
+        "archive": PollTransitionRule(
+            action="archive",
+            source_statuses=frozenset({"draft", "open", "closed", "decided"}),
+            target_status="archived",
+        ),
+        "unarchive": PollTransitionRule(
+            action="unarchive",
+            source_statuses=frozenset({"archived"}),
+            target_status=None,
+            restore_archived_status=True,
+            missing_restore_target_status="draft",
+        ),
+    }
+)
+
+
+class PollTransitionEngine:
+    """Pure lifecycle planner backed by an injected transition policy."""
+
+    def __init__(self, policy: PollTransitionPolicy = DEFAULT_POLL_TRANSITION_POLICY) -> None:
+        self.policy = policy
+
+    def plan(
+        self,
+        *,
+        current_status: str,
+        action: str,
+        archived_from_status: str | None = None,
+    ) -> PollTransitionPlan:
+        if current_status not in POLL_STATUSES:
+            raise ValueError(f"Unknown poll status: {current_status}")
+        rule = self.policy.rules.get(action)
+        if rule is None:
+            raise ValueError(f"Unknown poll transition action: {action}")
+        if current_status not in rule.source_statuses:
+            raise ValueError(f"Poll transition {action!r} is not allowed from status {current_status!r}")
+
+        target_status = rule.target_status
+        if rule.restore_archived_status:
+            if archived_from_status is None and rule.missing_restore_target_status is not None:
+                target_status = rule.missing_restore_target_status
+            elif archived_from_status not in POLL_STATUSES - {"archived"}:
+                raise ValueError("Archived poll has no valid status to restore")
+            else:
+                target_status = archived_from_status
+        if target_status is None:
+            raise ValueError(f"Poll transition {action!r} did not resolve a target status")
+        return PollTransitionPlan(action=action, from_status=current_status, to_status=target_status)
+
+    def available_actions(
+        self,
+        *,
+        current_status: str,
+        archived_from_status: str | None = None,
+    ) -> tuple[PollTransitionAvailability, ...]:
+        actions: list[PollTransitionAvailability] = []
+        for action in POLL_TRANSITION_ACTIONS:
+            rule = self.policy.rules[action]
+            target_status = (
+                archived_from_status or rule.missing_restore_target_status
+                if rule.restore_archived_status
+                else rule.target_status
+            )
+            try:
+                self.plan(
+                    current_status=current_status,
+                    action=action,
+                    archived_from_status=archived_from_status,
+                )
+            except ValueError as exc:
+                actions.append(
+                    PollTransitionAvailability(
+                        action=action,
+                        target_status=target_status,
+                        available=False,
+                        reason=str(exc),
+                    )
+                )
+            else:
+                actions.append(
+                    PollTransitionAvailability(
+                        action=action,
+                        target_status=target_status,
+                        available=True,
+                    )
+                )
+        return tuple(actions)
+
+
+DEFAULT_POLL_TRANSITION_ENGINE = PollTransitionEngine()
+
+
+__all__ = [
+    "DEFAULT_POLL_TRANSITION_ENGINE",
+    "DEFAULT_POLL_TRANSITION_POLICY",
+    "POLL_STATUSES",
+    "POLL_TRANSITION_ACTIONS",
+    "PollTransitionAvailability",
+    "PollTransitionEngine",
+    "PollTransitionPlan",
+    "PollTransitionPolicy",
+    "PollTransitionRule",
+]

tests/test_authorization.py

@@ -0,0 +1,306 @@
+from __future__ import annotations
+
+import unittest
+from types import SimpleNamespace
+
+from fastapi import HTTPException
+from sqlalchemy import create_engine
+from sqlalchemy.orm import Session, sessionmaker
+
+from govoplan_core.auth import ApiPrincipal
+from govoplan_core.core.access import PrincipalRef
+from govoplan_core.db.base import Base
+from govoplan_poll.backend.db.models import Poll, PollInvitation, PollLifecycleTransition, PollOption, PollResponse
+from govoplan_poll.backend.router import (
+    api_create_poll,
+    api_get_poll,
+    api_list_poll_invitations,
+    api_list_poll_responses,
+    api_list_polls,
+    api_poll_summary,
+    api_submit_poll_response,
+)
+from govoplan_poll.backend.schemas import (
+    PollAnswerInput,
+    PollCreateRequest,
+    PollInvitationCreateRequest,
+    PollSubmitResponseRequest,
+)
+from govoplan_poll.backend.service import close_poll, create_poll, create_poll_invitation, open_poll
+
+
+READ_SCOPE = "poll:poll:read"
+WRITE_SCOPE = "poll:poll:write"
+RESPOND_SCOPE = "poll:response:write"
+
+
+class PollAuthorizationTests(unittest.TestCase):
+    def setUp(self) -> None:
+        self.engine = create_engine("sqlite:///:memory:")
+        Base.metadata.create_all(
+            self.engine,
+            tables=[
+                Poll.__table__,
+                PollOption.__table__,
+                PollResponse.__table__,
+                PollInvitation.__table__,
+                PollLifecycleTransition.__table__,
+            ],
+        )
+        self.Session = sessionmaker(bind=self.engine)
+        self.session: Session = self.Session()
+
+    def tearDown(self) -> None:
+        self.session.close()
+        Base.metadata.drop_all(
+            self.engine,
+            tables=[
+                PollLifecycleTransition.__table__,
+                PollInvitation.__table__,
+                PollResponse.__table__,
+                PollOption.__table__,
+                Poll.__table__,
+            ],
+        )
+        self.engine.dispose()
+
+    @staticmethod
+    def _principal(
+        account_id: str,
+        *,
+        tenant_id: str = "tenant-1",
+        user_id: str | None = None,
+        scopes: set[str] | None = None,
+    ) -> ApiPrincipal:
+        membership_id = user_id or f"membership-{account_id}"
+        display_name = f"Actor {account_id}"
+        return ApiPrincipal(
+            principal=PrincipalRef(
+                account_id=account_id,
+                membership_id=membership_id,
+                tenant_id=tenant_id,
+                scopes=frozenset(scopes or {READ_SCOPE, RESPOND_SCOPE}),
+                display_name=display_name,
+            ),
+            account=SimpleNamespace(id=account_id),
+            user=SimpleNamespace(id=membership_id),
+        )
+
+    def _poll(
+        self,
+        *,
+        owner_id: str = "owner",
+        visibility: str = "tenant",
+        result_visibility: str = "after_close",
+        title: str = "Decision",
+    ) -> Poll:
+        poll = create_poll(
+            self.session,
+            tenant_id="tenant-1",
+            user_id=owner_id,
+            payload=PollCreateRequest(
+                title=title,
+                kind="yes_no",
+                visibility=visibility,
+                result_visibility=result_visibility,
+            ),
+        )
+        open_poll(self.session, tenant_id="tenant-1", poll_id=poll.id)
+        return poll
+
+    @staticmethod
+    def _answer(*, claimed_respondent: str = "victim") -> PollSubmitResponseRequest:
+        return PollSubmitResponseRequest(
+            respondent_id=claimed_respondent,
+            respondent_label="Claimed victim",
+            answers=[PollAnswerInput(option_key="yes")],
+        )
+
+    def test_authenticated_response_identity_is_bound_to_actor(self) -> None:
+        poll = self._poll(result_visibility="public")
+        first_actor = self._principal("account-1")
+        second_actor = self._principal("account-2")
+
+        first = api_submit_poll_response(
+            poll.id,
+            self._answer(),
+            session=self.session,
+            principal=first_actor,
+        )
+        second = api_submit_poll_response(
+            poll.id,
+            self._answer(),
+            session=self.session,
+            principal=second_actor,
+        )
+        updated_first = api_submit_poll_response(
+            poll.id,
+            PollSubmitResponseRequest(
+                respondent_id="account-2",
+                answers=[PollAnswerInput(option_key="no")],
+            ),
+            session=self.session,
+            principal=first_actor,
+        )
+
+        self.assertEqual(first.respondent_id, "account-1")
+        self.assertEqual(first.respondent_label, "Actor account-1")
+        self.assertEqual(second.respondent_id, "account-2")
+        self.assertNotEqual(first.id, second.id)
+        self.assertEqual(updated_first.id, first.id)
+        self.assertEqual(updated_first.answers[0]["option_key"], "no")
+
+        cross_tenant_actor = self._principal("account-1", tenant_id="tenant-2")
+        with self.assertRaises(HTTPException) as cross_tenant:
+            api_submit_poll_response(
+                poll.id,
+                self._answer(),
+                session=self.session,
+                principal=cross_tenant_actor,
+            )
+        self.assertEqual(cross_tenant.exception.status_code, 404)
+
+    def test_create_route_persists_after_request_session_closes(self) -> None:
+        created = api_create_poll(
+            PollCreateRequest(title="Persisted poll", kind="yes_no", visibility="tenant"),
+            session=self.session,
+            principal=self._principal("owner", scopes={WRITE_SCOPE}),
+        )
+
+        self.session.close()
+        self.session = self.Session()
+        persisted = self.session.query(Poll).filter(Poll.id == created.id).one_or_none()
+
+        self.assertIsNotNone(persisted)
+        self.assertEqual(persisted.title, "Persisted poll")
+
+    def test_authenticated_response_cannot_claim_an_invitation(self) -> None:
+        poll = self._poll(result_visibility="public")
+
+        response = api_submit_poll_response(
+            poll.id,
+            self._answer().model_copy(
+                update={"metadata": {"invitation_id": "forged-invitation", "client_note": "kept"}}
+            ),
+            session=self.session,
+            principal=self._principal("account-1"),
+        )
+
+        self.assertEqual(response.metadata, {"client_note": "kept"})
+
+    def test_private_poll_requires_ownership_management_or_active_assignment(self) -> None:
+        poll = self._poll(visibility="private")
+        reader = self._principal("reader")
+
+        listed = api_list_polls(
+            status_filter=None,
+            kind=None,
+            session=self.session,
+            principal=reader,
+        )
+        self.assertEqual(listed.polls, [])
+        with self.assertRaises(HTTPException) as hidden:
+            api_get_poll(poll.id, session=self.session, principal=reader)
+        self.assertEqual(hidden.exception.status_code, 404)
+
+        invitation, _token = create_poll_invitation(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+            payload=PollInvitationCreateRequest(respondent_id=reader.membership_id),
+        )
+        visible = api_get_poll(poll.id, session=self.session, principal=reader)
+        self.assertEqual(visible.id, poll.id)
+
+        invitation.revoked_at = invitation.created_at
+        self.session.flush()
+        with self.assertRaises(HTTPException) as revoked:
+            api_get_poll(poll.id, session=self.session, principal=reader)
+        self.assertEqual(revoked.exception.status_code, 404)
+
+        manager = self._principal("manager", scopes={READ_SCOPE, WRITE_SCOPE})
+        self.assertEqual(api_get_poll(poll.id, session=self.session, principal=manager).id, poll.id)
+
+        other_tenant = self._principal("owner", tenant_id="tenant-2", scopes={READ_SCOPE, WRITE_SCOPE})
+        with self.assertRaises(HTTPException) as cross_tenant:
+            api_get_poll(poll.id, session=self.session, principal=other_tenant)
+        self.assertEqual(cross_tenant.exception.status_code, 404)
+
+    def test_after_response_results_do_not_leak_to_other_actors(self) -> None:
+        poll = self._poll(result_visibility="after_response")
+        respondent = self._principal("respondent")
+        bystander = self._principal("bystander")
+
+        with self.assertRaises(HTTPException) as before_response:
+            api_poll_summary(poll.id, session=self.session, principal=respondent)
+        self.assertEqual(before_response.exception.status_code, 403)
+
+        api_submit_poll_response(poll.id, self._answer(), session=self.session, principal=respondent)
+        self.assertEqual(api_poll_summary(poll.id, session=self.session, principal=respondent).response_count, 1)
+        with self.assertRaises(HTTPException) as own_raw_responses:
+            api_list_poll_responses(poll.id, session=self.session, principal=respondent)
+        self.assertEqual(own_raw_responses.exception.status_code, 403)
+
+        with self.assertRaises(HTTPException) as other_actor_summary:
+            api_poll_summary(poll.id, session=self.session, principal=bystander)
+        self.assertEqual(other_actor_summary.exception.status_code, 403)
+        with self.assertRaises(HTTPException) as other_actor_responses:
+            api_list_poll_responses(poll.id, session=self.session, principal=bystander)
+        self.assertEqual(other_actor_responses.exception.status_code, 403)
+
+    def test_participants_can_see_aggregate_but_not_raw_responses_or_invitation_roster(self) -> None:
+        poll = self._poll(result_visibility="public")
+        first_actor = self._principal("account-1")
+        second_actor = self._principal("account-2")
+        create_poll_invitation(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+            payload=PollInvitationCreateRequest(respondent_id=first_actor.membership_id, email="one@example.test"),
+        )
+        create_poll_invitation(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+            payload=PollInvitationCreateRequest(respondent_id=second_actor.membership_id, email="two@example.test"),
+        )
+        api_submit_poll_response(poll.id, self._answer(), session=self.session, principal=first_actor)
+        api_submit_poll_response(poll.id, self._answer(), session=self.session, principal=second_actor)
+
+        self.assertEqual(api_poll_summary(poll.id, session=self.session, principal=first_actor).response_count, 2)
+        with self.assertRaises(HTTPException) as raw_responses:
+            api_list_poll_responses(poll.id, session=self.session, principal=first_actor)
+        self.assertEqual(raw_responses.exception.status_code, 403)
+        with self.assertRaises(HTTPException) as invitation_roster:
+            api_list_poll_invitations(poll.id, session=self.session, principal=first_actor)
+        self.assertEqual(invitation_roster.exception.status_code, 403)
+
+        organizer = self._principal("owner", scopes={READ_SCOPE})
+        self.assertEqual(len(api_list_poll_responses(poll.id, session=self.session, principal=organizer).responses), 2)
+        self.assertEqual(len(api_list_poll_invitations(poll.id, session=self.session, principal=organizer).invitations), 2)
+        manager = self._principal("manager", scopes={WRITE_SCOPE})
+        self.assertEqual(len(api_list_poll_responses(poll.id, session=self.session, principal=manager).responses), 2)
+        self.assertEqual(len(api_list_poll_invitations(poll.id, session=self.session, principal=manager).invitations), 2)
+
+    def test_after_close_and_organizer_result_visibility_are_enforced(self) -> None:
+        after_close = self._poll(result_visibility="after_close", title="After close")
+        reader = self._principal("reader")
+
+        with self.assertRaises(HTTPException) as still_open:
+            api_poll_summary(after_close.id, session=self.session, principal=reader)
+        self.assertEqual(still_open.exception.status_code, 403)
+        close_poll(self.session, tenant_id="tenant-1", poll_id=after_close.id)
+        self.assertEqual(api_poll_summary(after_close.id, session=self.session, principal=reader).response_count, 0)
+
+        organizer_only = self._poll(result_visibility="organizer", title="Organizer only")
+        api_submit_poll_response(organizer_only.id, self._answer(), session=self.session, principal=reader)
+        with self.assertRaises(HTTPException) as participant_denied:
+            api_poll_summary(organizer_only.id, session=self.session, principal=reader)
+        self.assertEqual(participant_denied.exception.status_code, 403)
+
+        owner = self._principal("owner", scopes={READ_SCOPE})
+        self.assertEqual(api_poll_summary(organizer_only.id, session=self.session, principal=owner).response_count, 1)
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/test_lifecycle.py

@@ -0,0 +1,563 @@
+from __future__ import annotations
+
+import unittest
+from datetime import datetime, timedelta, timezone
+from types import SimpleNamespace
+
+from fastapi import HTTPException
+from pydantic import ValidationError
+from sqlalchemy import create_engine
+from sqlalchemy.orm import Session, sessionmaker
+
+from govoplan_core.auth import ApiPrincipal
+from govoplan_core.core.access import PrincipalRef
+from govoplan_core.db.base import Base
+from govoplan_poll.backend.db.models import (
+    Poll,
+    PollInvitation,
+    PollLifecycleTransition,
+    PollOption,
+    PollResponse,
+)
+from govoplan_poll.backend.router import api_poll_lifecycle, api_transition_poll
+from govoplan_poll.backend.schemas import (
+    PollAnswerInput,
+    PollCreateRequest,
+    PollOptionInput,
+    PollSubmitResponseRequest,
+    PollTransitionRequest,
+)
+from govoplan_poll.backend.service import (
+    PollError,
+    create_poll,
+    list_poll_lifecycle_transitions,
+    poll_response,
+    poll_results_are_visible,
+    response_datetime,
+    submit_poll_response,
+    transition_poll,
+)
+from govoplan_poll.backend.transitions import (
+    DEFAULT_POLL_TRANSITION_POLICY,
+    PollTransitionEngine,
+    PollTransitionPolicy,
+    PollTransitionRule,
+)
+
+
+WRITE_SCOPE = "poll:poll:write"
+
+
+class PollLifecycleTests(unittest.TestCase):
+    def setUp(self) -> None:
+        self.engine = create_engine("sqlite:///:memory:")
+        Base.metadata.create_all(
+            self.engine,
+            tables=[
+                Poll.__table__,
+                PollOption.__table__,
+                PollResponse.__table__,
+                PollInvitation.__table__,
+                PollLifecycleTransition.__table__,
+            ],
+        )
+        self.Session = sessionmaker(bind=self.engine)
+        self.session: Session = self.Session()
+
+    def tearDown(self) -> None:
+        self.session.close()
+        Base.metadata.drop_all(
+            self.engine,
+            tables=[
+                PollLifecycleTransition.__table__,
+                PollInvitation.__table__,
+                PollResponse.__table__,
+                PollOption.__table__,
+                Poll.__table__,
+            ],
+        )
+        self.engine.dispose()
+
+    def _poll(self, *, status: str = "draft", title: str = "Decision") -> Poll:
+        return create_poll(
+            self.session,
+            tenant_id="tenant-1",
+            user_id="owner",
+            payload=PollCreateRequest(
+                title=title,
+                kind="single_choice",
+                status=status,
+                visibility="tenant",
+                options=[
+                    PollOptionInput(key="yes", label="Yes"),
+                    PollOptionInput(key="no", label="No"),
+                ],
+            ),
+        )
+
+    @staticmethod
+    def _principal() -> ApiPrincipal:
+        return ApiPrincipal(
+            principal=PrincipalRef(
+                account_id="owner",
+                membership_id="owner-membership",
+                tenant_id="tenant-1",
+                scopes=frozenset({WRITE_SCOPE}),
+                display_name="Owner",
+            ),
+            account=SimpleNamespace(id="owner"),
+            user=SimpleNamespace(id="owner-membership"),
+        )
+
+    def test_default_policy_exposes_every_allowed_and_rejected_transition(self) -> None:
+        expected = {
+            "draft": {"open", "archive"},
+            "open": {"draft", "close", "archive"},
+            "closed": {"open", "decide", "archive"},
+            "decided": {"open", "decide", "archive"},
+            "archived": {"unarchive"},
+        }
+        engine = PollTransitionEngine()
+
+        for status, allowed in expected.items():
+            archived_from_status = "closed" if status == "archived" else None
+            availability = engine.available_actions(
+                current_status=status,
+                archived_from_status=archived_from_status,
+            )
+            self.assertEqual({item.action for item in availability if item.available}, allowed)
+            for item in availability:
+                if item.available:
+                    self.assertIsNone(item.reason)
+                else:
+                    self.assertTrue(item.reason)
+
+        with self.assertRaisesRegex(ValueError, "not allowed"):
+            engine.plan(current_status="draft", action="close")
+
+    def test_injected_policy_governs_service_transition_and_projection(self) -> None:
+        rules = dict(DEFAULT_POLL_TRANSITION_POLICY.rules)
+        rules["close"] = PollTransitionRule(
+            action="close",
+            source_statuses=frozenset({"draft", "open"}),
+            target_status="closed",
+        )
+        custom_engine = PollTransitionEngine(PollTransitionPolicy(rules))
+        poll = self._poll()
+
+        projected = poll_response(poll, transition_engine=custom_engine)
+        close_action = next(item for item in projected["lifecycle_actions"] if item["action"] == "close")
+        result = transition_poll(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+            action="close",
+            transition_engine=custom_engine,
+        )
+
+        self.assertTrue(close_action["available"])
+        self.assertEqual(result.poll.status, "closed")
+        self.assertEqual(result.transition.from_status, "draft")
+
+    def test_only_draft_or_open_are_valid_initial_states(self) -> None:
+        for initial_status in ("closed", "decided", "archived"):
+            with self.subTest(initial_status=initial_status):
+                with self.assertRaises(ValidationError):
+                    PollCreateRequest(title="Invalid initial state", kind="yes_no", status=initial_status)
+
+        bypassed_schema = PollCreateRequest(title="Invalid initial state", kind="yes_no").model_copy(
+            update={"status": "closed"}
+        )
+        with self.assertRaisesRegex(PollError, "initial status must be draft or open"):
+            create_poll(
+                self.session,
+                tenant_id="tenant-1",
+                user_id="owner",
+                payload=bypassed_schema,
+            )
+
+    def test_reopening_preserves_responses_close_history_and_previous_decision(self) -> None:
+        poll = self._poll()
+        transition_poll(self.session, tenant_id="tenant-1", poll_id=poll.id, action="open")
+        response = submit_poll_response(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+            payload=PollSubmitResponseRequest(
+                respondent_id="participant",
+                answers=[PollAnswerInput(option_key="yes")],
+            ),
+        )
+        transition_poll(self.session, tenant_id="tenant-1", poll_id=poll.id, action="close")
+        first_closed_at = poll.closed_at
+        transition_poll(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+            action="decide",
+            option_key="yes",
+        )
+        decided_at = poll.decided_at
+        decided_option_id = poll.decided_option_id
+
+        transition_poll(self.session, tenant_id="tenant-1", poll_id=poll.id, action="open")
+
+        self.assertEqual(poll.status, "open")
+        self.assertEqual(response_datetime(poll.closed_at), response_datetime(first_closed_at))
+        self.assertEqual(response_datetime(poll.decided_at), response_datetime(decided_at))
+        self.assertEqual(poll.decided_option_id, decided_option_id)
+        self.assertEqual(response.deleted_at, None)
+        self.assertEqual(response.answers[0]["option_key"], "yes")
+        history = list_poll_lifecycle_transitions(self.session, tenant_id="tenant-1", poll_id=poll.id)
+        self.assertEqual([item.action for item in history], ["open", "close", "decide", "open"])
+
+    def test_direct_redecision_is_audited_and_exact_retry_is_idempotent(self) -> None:
+        poll = self._poll()
+        transition_poll(self.session, tenant_id="tenant-1", poll_id=poll.id, action="open")
+        transition_poll(self.session, tenant_id="tenant-1", poll_id=poll.id, action="close")
+        first = transition_poll(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+            action="decide",
+            option_key="yes",
+            idempotency_key="decision-1",
+        )
+        replay = transition_poll(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+            action="decide",
+            option_key="yes",
+            idempotency_key="decision-1",
+        )
+        second = transition_poll(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+            action="decide",
+            option_key="no",
+            idempotency_key="decision-2",
+        )
+
+        self.assertFalse(first.replayed)
+        self.assertTrue(replay.replayed)
+        self.assertEqual(replay.transition.id, first.transition.id)
+        self.assertFalse(second.replayed)
+        self.assertEqual(second.transition.previous_decision_option_id, first.transition.decision_option_id)
+        self.assertEqual(poll.decided_option_id, second.transition.decision_option_id)
+        self.assertEqual(
+            self.session.query(PollLifecycleTransition)
+            .filter(
+                PollLifecycleTransition.poll_id == poll.id,
+                PollLifecycleTransition.action == "decide",
+            )
+            .count(),
+            2,
+        )
+
+        with self.assertRaisesRegex(PollError, "different poll transition"):
+            transition_poll(
+                self.session,
+                tenant_id="tenant-1",
+                poll_id=poll.id,
+                action="decide",
+                option_key="yes",
+                idempotency_key="decision-2",
+            )
+
+    def test_repeated_exact_transition_without_an_identity_is_an_audit_free_noop(self) -> None:
+        poll = self._poll()
+        applied = transition_poll(self.session, tenant_id="tenant-1", poll_id=poll.id, action="open")
+
+        with self.assertLogs("govoplan.poll.lifecycle", level="INFO") as logs:
+            repeated = transition_poll(
+                self.session,
+                tenant_id="tenant-1",
+                poll_id=poll.id,
+                action="open",
+                actor_user_id="owner",
+            )
+
+        self.assertFalse(applied.replayed)
+        self.assertTrue(repeated.replayed)
+        self.assertIsNone(repeated.transition)
+        self.assertEqual(poll.status, "open")
+        self.assertEqual(len(poll.lifecycle_transitions), 1)
+        self.assertIn("Ignored repeated exact Poll lifecycle transition", logs.output[0])
+
+    def test_same_decision_is_a_noop_but_a_changed_decision_is_audited(self) -> None:
+        poll = self._poll()
+        transition_poll(self.session, tenant_id="tenant-1", poll_id=poll.id, action="open")
+        transition_poll(self.session, tenant_id="tenant-1", poll_id=poll.id, action="close")
+        first = transition_poll(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+            action="decide",
+            option_key="yes",
+        )
+        repeated = transition_poll(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+            action="decide",
+            option_key="yes",
+        )
+        changed = transition_poll(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+            action="decide",
+            option_key="no",
+        )
+
+        self.assertTrue(repeated.replayed)
+        self.assertIsNone(repeated.transition)
+        self.assertIsNotNone(first.transition)
+        self.assertIsNotNone(changed.transition)
+        self.assertEqual(changed.transition.previous_decision_option_id, first.transition.decision_option_id)
+        self.assertEqual(
+            [item.action for item in poll.lifecycle_transitions],
+            ["open", "close", "decide", "decide"],
+        )
+
+    def test_exact_unarchive_retry_is_a_noop_but_unarchive_without_history_is_invalid(self) -> None:
+        poll = self._poll()
+        transition_poll(self.session, tenant_id="tenant-1", poll_id=poll.id, action="archive")
+        transition_poll(self.session, tenant_id="tenant-1", poll_id=poll.id, action="unarchive")
+
+        repeated = transition_poll(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+            action="unarchive",
+        )
+
+        self.assertTrue(repeated.replayed)
+        self.assertIsNone(repeated.transition)
+        self.assertEqual([item.action for item in poll.lifecycle_transitions], ["archive", "unarchive"])
+
+        never_archived = self._poll(title="Never archived")
+        with self.assertRaisesRegex(PollError, "not allowed"):
+            transition_poll(
+                self.session,
+                tenant_id="tenant-1",
+                poll_id=never_archived.id,
+                action="unarchive",
+            )
+
+    def test_archive_and_unarchive_restore_status_and_append_audit_history(self) -> None:
+        poll = self._poll()
+        transition_poll(self.session, tenant_id="tenant-1", poll_id=poll.id, action="open")
+        transition_poll(self.session, tenant_id="tenant-1", poll_id=poll.id, action="close")
+        response = PollResponse(
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+            respondent_id="participant",
+            answers=[{"option_key": "yes"}],
+            submitted_at=poll.created_at,
+        )
+        self.session.add(response)
+        self.session.flush()
+
+        archived = transition_poll(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+            action="archive",
+            idempotency_key="archive-1",
+        )
+        restored = transition_poll(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+            action="unarchive",
+            idempotency_key="unarchive-1",
+        )
+
+        self.assertEqual(archived.transition.to_status, "archived")
+        self.assertEqual(restored.transition.to_status, "closed")
+        self.assertEqual(poll.status, "closed")
+        self.assertIsNone(poll.archived_from_status)
+        self.assertIsNone(response.deleted_at)
+        self.assertEqual(
+            [item.action for item in poll.lifecycle_transitions],
+            ["open", "close", "archive", "unarchive"],
+        )
+
+    def test_legacy_archive_without_origin_restores_to_draft_with_audit_marker(self) -> None:
+        poll = Poll(
+            tenant_id="tenant-1",
+            slug="legacy-archive",
+            title="Legacy archive",
+            kind="yes_no",
+            status="archived",
+            visibility="tenant",
+            result_visibility="after_close",
+            workflow_steps=[],
+            allow_anonymous=False,
+            allow_response_update=True,
+            min_choices=1,
+        )
+        self.session.add(poll)
+        self.session.flush()
+
+        restored = transition_poll(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+            action="unarchive",
+        )
+
+        self.assertEqual(restored.poll.status, "draft")
+        self.assertEqual(restored.transition.to_status, "draft")
+        self.assertEqual(
+            restored.transition.metadata_["legacy_restore_fallback"],
+            {
+                "reason": "missing_archived_from_status",
+                "restored_status": "draft",
+            },
+        )
+
+    def test_reopening_clears_only_an_expired_deadline_and_preserves_close_history(self) -> None:
+        poll = self._poll()
+        transition_poll(self.session, tenant_id="tenant-1", poll_id=poll.id, action="open")
+        transition_poll(self.session, tenant_id="tenant-1", poll_id=poll.id, action="close")
+        closed_at = poll.closed_at
+        expired_deadline = datetime.now(timezone.utc) - timedelta(days=1)
+        poll.closes_at = expired_deadline
+
+        reopened = transition_poll(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+            action="open",
+        )
+
+        self.assertEqual(reopened.poll.status, "open")
+        self.assertIsNone(reopened.poll.closes_at)
+        self.assertEqual(response_datetime(reopened.poll.closed_at), response_datetime(closed_at))
+        self.assertEqual(
+            reopened.transition.metadata_["cleared_expired_closes_at"],
+            expired_deadline.isoformat(),
+        )
+        submit_poll_response(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+            payload=PollSubmitResponseRequest(
+                respondent_id="participant-after-reopen",
+                answers=[PollAnswerInput(option_key="yes")],
+            ),
+        )
+
+        future_deadline = datetime.now(timezone.utc) + timedelta(days=1)
+        future_poll = self._poll(title="Future deadline")
+        future_poll.closes_at = future_deadline
+        opened = transition_poll(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=future_poll.id,
+            action="open",
+        )
+        self.assertEqual(response_datetime(opened.poll.closes_at), future_deadline)
+        self.assertNotIn("cleared_expired_closes_at", opened.transition.metadata_)
+
+    def test_archiving_draft_or_open_poll_does_not_grant_after_close_visibility(self) -> None:
+        for initial_status in ("draft", "open"):
+            with self.subTest(initial_status=initial_status):
+                poll = self._poll(status=initial_status, title=f"Archive from {initial_status}")
+                transition_poll(
+                    self.session,
+                    tenant_id="tenant-1",
+                    poll_id=poll.id,
+                    action="archive",
+                )
+
+                self.assertFalse(
+                    poll_results_are_visible(
+                        self.session,
+                        poll=poll,
+                        actor_ids=("participant",),
+                    )
+                )
+
+        closed_poll = self._poll(title="Archive from closed")
+        transition_poll(self.session, tenant_id="tenant-1", poll_id=closed_poll.id, action="open")
+        transition_poll(self.session, tenant_id="tenant-1", poll_id=closed_poll.id, action="close")
+        transition_poll(self.session, tenant_id="tenant-1", poll_id=closed_poll.id, action="archive")
+        self.assertTrue(
+            poll_results_are_visible(
+                self.session,
+                poll=closed_poll,
+                actor_ids=("participant",),
+            )
+        )
+
+    def test_generic_api_returns_action_availability_history_and_actor(self) -> None:
+        poll = self._poll()
+        principal = self._principal()
+
+        opened = api_transition_poll(
+            poll.id,
+            PollTransitionRequest(action="open"),
+            idempotency_key="open-api-1",
+            session=self.session,
+            principal=principal,
+        )
+        replay = api_transition_poll(
+            poll.id,
+            PollTransitionRequest(action="open"),
+            idempotency_key="open-api-1",
+            session=self.session,
+            principal=principal,
+        )
+        lifecycle = api_poll_lifecycle(poll.id, session=self.session, principal=principal)
+
+        self.assertEqual(opened.poll.status, "open")
+        self.assertFalse(opened.replayed)
+        self.assertTrue(replay.replayed)
+        self.assertIsNotNone(replay.transition)
+        self.assertEqual(len(lifecycle.history), 1)
+        self.assertEqual(lifecycle.history[0].actor_user_id, "owner-membership")
+        self.assertEqual(
+            {item.action for item in lifecycle.actions if item.available},
+            {"draft", "close", "archive"},
+        )
+
+        draft = self._poll(title="Draft cannot close")
+        with self.assertRaises(HTTPException) as rejected:
+            api_transition_poll(
+                draft.id,
+                PollTransitionRequest(action="close"),
+                idempotency_key=None,
+                session=self.session,
+                principal=principal,
+            )
+        self.assertEqual(rejected.exception.status_code, 400)
+
+    def test_generic_api_returns_null_transition_for_domain_noop(self) -> None:
+        poll = self._poll(status="open", title="Already open")
+
+        repeated = api_transition_poll(
+            poll.id,
+            PollTransitionRequest(action="open"),
+            idempotency_key=None,
+            session=self.session,
+            principal=self._principal(),
+        )
+
+        self.assertEqual(repeated.poll.status, "open")
+        self.assertTrue(repeated.replayed)
+        self.assertIsNone(repeated.transition)
+        self.assertEqual(
+            self.session.query(PollLifecycleTransition)
+            .filter(PollLifecycleTransition.poll_id == poll.id)
+            .count(),
+            0,
+        )
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/test_manifest.py

@@ -4,6 +4,7 @@ import unittest
 
 from govoplan_core.core.modules import ModuleManifest
 from govoplan_poll.backend.manifest import get_manifest
+from govoplan_poll.backend.participation import CAPABILITY_POLL_PARTICIPATION_GATEWAY
 
 
 class PollManifestTests(unittest.TestCase):
@@ -21,6 +22,9 @@ class PollManifestTests(unittest.TestCase):
         self.assertIn("poll.availability_matrix", {interface.name for interface in manifest.provides_interfaces})
         self.assertIn("poll.workflow_context", {interface.name for interface in manifest.provides_interfaces})
         self.assertIn("poll.signed_participation", {interface.name for interface in manifest.provides_interfaces})
+        self.assertIn("poll.governed_participation", {interface.name for interface in manifest.provides_interfaces})
+        self.assertIn(CAPABILITY_POLL_PARTICIPATION_GATEWAY, manifest.capability_factories)
+        self.assertEqual(manifest.version, "0.1.11")
         self.assertIn("poll:response:write", {permission.scope for permission in manifest.permissions})
 
 

tests/test_migrations.py

@@ -0,0 +1,210 @@
+from __future__ import annotations
+
+import tempfile
+import unittest
+from datetime import datetime, timedelta, timezone
+from pathlib import Path
+
+from alembic import command
+from alembic.runtime.migration import MigrationContext
+from sqlalchemy import create_engine, inspect
+from sqlalchemy.exc import IntegrityError
+from sqlalchemy.orm import Session
+
+from govoplan_core.db.migrations import alembic_config
+from govoplan_poll.backend.db.models import PollResponse
+from govoplan_poll.backend.manifest import get_manifest
+from govoplan_poll.backend.schemas import (
+    PollCreateRequest,
+    PollOptionInput,
+)
+from govoplan_poll.backend.service import _existing_response, create_poll
+
+
+_PREVIOUS_POLL_HEAD = "5d6e7f8a9b0c"
+_POLL_HEAD = "6e7f8a9b0c1d"
+_INDEX_NAME = "uq_poll_responses_active_respondent"
+
+
+class PollMigrationTests(unittest.TestCase):
+    @staticmethod
+    def _config(url: str):
+        return alembic_config(
+            database_url=url,
+            enabled_modules=("poll",),
+            manifest_factories=(get_manifest,),
+        )
+
+    def test_deduplicates_deterministically_and_enforces_partial_index(self) -> None:
+        with tempfile.TemporaryDirectory(
+            prefix="govoplan-poll-migration-"
+        ) as directory:
+            url = f"sqlite:///{Path(directory) / 'poll.db'}"
+            config = self._config(url)
+            command.upgrade(config, _PREVIOUS_POLL_HEAD)
+            engine = create_engine(url)
+            latest = datetime(2026, 7, 22, 10, 0, tzinfo=timezone.utc)
+            historical_deleted_at = latest - timedelta(days=2)
+            historical_updated_at = latest - timedelta(days=1)
+            try:
+                with Session(engine) as session:
+                    poll = create_poll(
+                        session,
+                        tenant_id="tenant-1",
+                        user_id="owner-1",
+                        payload=PollCreateRequest(
+                            title="Migration probe",
+                            kind="single_choice",
+                            status="open",
+                            allow_anonymous=True,
+                            options=[
+                                PollOptionInput(key="yes", label="Yes"),
+                                PollOptionInput(key="no", label="No"),
+                            ],
+                        ),
+                    )
+                    poll_id = poll.id
+                    session.add_all(
+                        [
+                            PollResponse(
+                                id="identified-oldest",
+                                tenant_id="tenant-1",
+                                poll_id=poll_id,
+                                respondent_id="person-1",
+                                answers=[],
+                                submitted_at=latest - timedelta(hours=1),
+                            ),
+                            PollResponse(
+                                id="identified-latest-a",
+                                tenant_id="tenant-1",
+                                poll_id=poll_id,
+                                respondent_id="person-1",
+                                answers=[],
+                                submitted_at=latest,
+                            ),
+                            PollResponse(
+                                id="identified-latest-b",
+                                tenant_id="tenant-1",
+                                poll_id=poll_id,
+                                respondent_id="person-1",
+                                answers=[],
+                                submitted_at=latest,
+                            ),
+                            PollResponse(
+                                id="anonymous-a",
+                                tenant_id="tenant-1",
+                                poll_id=poll_id,
+                                respondent_id=None,
+                                answers=[],
+                                submitted_at=latest,
+                            ),
+                            PollResponse(
+                                id="anonymous-b",
+                                tenant_id="tenant-1",
+                                poll_id=poll_id,
+                                respondent_id=None,
+                                answers=[],
+                                submitted_at=latest,
+                            ),
+                            PollResponse(
+                                id="already-deleted",
+                                tenant_id="tenant-1",
+                                poll_id=poll_id,
+                                respondent_id="person-1",
+                                answers=[],
+                                submitted_at=latest + timedelta(hours=1),
+                                deleted_at=historical_deleted_at,
+                                updated_at=historical_updated_at,
+                            ),
+                        ]
+                    )
+                    session.flush()
+                    self.assertEqual(
+                        _existing_response(
+                            session,
+                            poll=poll,
+                            respondent_id="person-1",
+                        ).id,
+                        "identified-latest-b",
+                    )
+                    session.commit()
+
+                command.upgrade(config, "heads")
+
+                with Session(engine) as session:
+                    rows = {
+                        response.id: response
+                        for response in session.query(PollResponse).all()
+                    }
+                    self.assertIsNone(rows["identified-latest-b"].deleted_at)
+                    tombstoned = (
+                        rows["identified-oldest"],
+                        rows["identified-latest-a"],
+                    )
+                    self.assertTrue(
+                        all(response.deleted_at is not None for response in tombstoned)
+                    )
+                    self.assertTrue(
+                        all(
+                            response.deleted_at == response.updated_at
+                            for response in tombstoned
+                        )
+                    )
+                    self.assertEqual(
+                        len({response.deleted_at for response in tombstoned}),
+                        1,
+                    )
+                    self.assertIsNone(rows["anonymous-a"].deleted_at)
+                    self.assertIsNone(rows["anonymous-b"].deleted_at)
+                    self.assertEqual(
+                        rows["already-deleted"].deleted_at,
+                        historical_deleted_at.replace(tzinfo=None),
+                    )
+                    self.assertEqual(
+                        rows["already-deleted"].updated_at,
+                        historical_updated_at.replace(tzinfo=None),
+                    )
+
+                    session.add(
+                        PollResponse(
+                            tenant_id="tenant-1",
+                            poll_id=poll_id,
+                            respondent_id="person-1",
+                            answers=[],
+                            submitted_at=latest + timedelta(hours=2),
+                        )
+                    )
+                    with self.assertRaises(IntegrityError):
+                        session.flush()
+                    session.rollback()
+
+                    session.add(
+                        PollResponse(
+                            tenant_id="tenant-1",
+                            poll_id=poll_id,
+                            respondent_id=None,
+                            answers=[],
+                            submitted_at=latest + timedelta(hours=2),
+                        )
+                    )
+                    session.commit()
+
+                with engine.connect() as connection:
+                    heads = set(
+                        MigrationContext.configure(connection).get_current_heads()
+                    )
+                    indexes = {
+                        item["name"]: item
+                        for item in inspect(connection).get_indexes(
+                            "poll_responses"
+                        )
+                    }
+                self.assertIn(_POLL_HEAD, heads)
+                self.assertIn(_INDEX_NAME, indexes)
+                self.assertTrue(indexes[_INDEX_NAME]["unique"])
+            finally:
+                engine.dispose()
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/test_participation_contract.py

@@ -0,0 +1,32 @@
+from __future__ import annotations
+
+import unittest
+
+from govoplan_core.core.poll_participation import (
+    CAPABILITY_POLL_PARTICIPATION_GATEWAY as CORE_CAPABILITY,
+    PollGovernedInvitationCommand as CorePollGovernedInvitationCommand,
+    PollParticipationGatewayProvider as CorePollParticipationGatewayProvider,
+    PollParticipationPolicy as CorePollParticipationPolicy,
+)
+from govoplan_poll.backend.capabilities import SqlPollSchedulingProvider
+from govoplan_poll.backend.participation import (
+    CAPABILITY_POLL_PARTICIPATION_GATEWAY,
+    PollGovernedInvitationCommand,
+    PollParticipationGatewayProvider,
+    PollParticipationPolicy,
+)
+
+
+class PollParticipationCompatibilityTests(unittest.TestCase):
+    def test_legacy_imports_are_exact_core_contract_re_exports(self) -> None:
+        self.assertIs(CORE_CAPABILITY, CAPABILITY_POLL_PARTICIPATION_GATEWAY)
+        self.assertIs(CorePollGovernedInvitationCommand, PollGovernedInvitationCommand)
+        self.assertIs(CorePollParticipationPolicy, PollParticipationPolicy)
+        self.assertIs(CorePollParticipationGatewayProvider, PollParticipationGatewayProvider)
+
+    def test_sql_provider_implements_the_core_contract(self) -> None:
+        self.assertIsInstance(SqlPollSchedulingProvider(), CorePollParticipationGatewayProvider)
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/test_response_editing.py

@@ -0,0 +1,297 @@
+from __future__ import annotations
+
+import unittest
+
+from sqlalchemy import create_engine
+from sqlalchemy.orm import Session, sessionmaker
+
+from govoplan_core.core.poll import (
+    PollCapabilityError,
+    PollOptionOrderCommand,
+    PollOptionUpdateCommand,
+    PollResponseRetirementCommand,
+    PollResponseRetirementProvider,
+    PollSchedulingProvider,
+)
+from govoplan_core.db.base import Base
+from govoplan_poll.backend.capabilities import SqlPollSchedulingProvider
+from govoplan_poll.backend.db.models import Poll, PollOption, PollResponse
+from govoplan_poll.backend.schemas import PollAnswerInput, PollCreateRequest, PollOptionInput, PollSubmitResponseRequest
+from govoplan_poll.backend.service import create_poll, submit_poll_response
+
+
+class PollResponseEditingTests(unittest.TestCase):
+    def setUp(self) -> None:
+        self.engine = create_engine("sqlite:///:memory:")
+        Base.metadata.create_all(
+            self.engine,
+            tables=[Poll.__table__, PollOption.__table__, PollResponse.__table__],
+        )
+        self.Session = sessionmaker(bind=self.engine)
+        self.session: Session = self.Session()
+
+    def tearDown(self) -> None:
+        self.session.close()
+        Base.metadata.drop_all(
+            self.engine,
+            tables=[PollResponse.__table__, PollOption.__table__, Poll.__table__],
+        )
+        self.engine.dispose()
+
+    def _poll(self, *, allow_response_update: bool = True) -> Poll:
+        return create_poll(
+            self.session,
+            tenant_id="tenant-1",
+            user_id="organizer-1",
+            payload=PollCreateRequest(
+                title="Availability",
+                kind="availability",
+                status="open",
+                min_choices=1,
+                max_choices=2,
+                allow_response_update=allow_response_update,
+                options=[
+                    PollOptionInput(
+                        key="slot-1",
+                        label="Monday",
+                        value={"slot_id": "slot-1"},
+                        metadata={"source": "scheduling"},
+                    ),
+                    PollOptionInput(
+                        key="slot-2",
+                        label="Tuesday",
+                        value={"slot_id": "slot-2"},
+                    ),
+                ],
+            ),
+        )
+
+    def _submit_both(self, poll: Poll, respondent_id: str) -> PollResponse:
+        return submit_poll_response(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+            payload=PollSubmitResponseRequest(
+                respondent_id=respondent_id,
+                answers=[
+                    PollAnswerInput(option_id=poll.options[0].id, value="available"),
+                    PollAnswerInput(option_id=poll.options[1].id, value="maybe"),
+                ],
+            ),
+        )
+
+    def test_provider_projects_answers_and_option_change_invalidates_only_that_option(self) -> None:
+        poll = self._poll()
+        first = self._submit_both(poll, "person-1")
+        second = self._submit_both(poll, "person-2")
+        provider = SqlPollSchedulingProvider()
+
+        self.assertIsInstance(provider, PollSchedulingProvider)
+        projected = provider.list_responses(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+        )
+        self.assertEqual([answer.value for answer in projected[0].answers], ["available", "maybe"])
+        current = provider.get_response(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+            respondent_ids=("person-1",),
+        )
+        self.assertIsNotNone(current)
+        self.assertEqual([answer.value for answer in current.answers], ["available", "maybe"])
+
+        option_ref = provider.update_option(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+            option_id=poll.options[0].id,
+            command=PollOptionUpdateCommand(
+                label="Monday, revised",
+                value={"slot_id": "slot-1"},
+                metadata={"source": "scheduling"},
+            ),
+        )
+
+        self.assertEqual(option_ref.id, poll.options[0].id)
+        self.assertEqual(first.answers, [{"option_id": poll.options[1].id, "option_key": "slot-2", "value": "maybe"}])
+        self.assertEqual(second.answers, [{"option_id": poll.options[1].id, "option_key": "slot-2", "value": "maybe"}])
+
+        # Re-answer, then replay the exact option snapshot. No response data is
+        # invalidated because the option did not actually change.
+        first = self._submit_both(poll, "person-1")
+        provider.update_option(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+            option_id=poll.options[0].id,
+            command=PollOptionUpdateCommand(
+                label="Monday, revised",
+                value={"slot_id": "slot-1"},
+                metadata={"source": "scheduling"},
+            ),
+        )
+        self.assertEqual(len(first.answers), 2)
+
+    def test_provider_retires_response_from_live_results_but_keeps_audit_history(self) -> None:
+        poll = self._poll()
+        response = self._submit_both(poll, "person-1")
+        response.metadata_ = {
+            "invitation_id": "invitation-1",
+            "participant_email": "alice@example.test",
+        }
+        provider = SqlPollSchedulingProvider()
+        command = PollResponseRetirementCommand(
+            respondent_ids=("person-1", "alice@example.test"),
+            invitation_id="invitation-1",
+            reason="scheduling_participant_removed",
+            idempotency_key="scheduling:request-1:participant-1:removed",
+            metadata={
+                "source_module": "scheduling",
+                "source_resource_type": "participant",
+                "source_resource_id": "participant-1",
+            },
+        )
+
+        self.assertIsInstance(provider, PollResponseRetirementProvider)
+        retired = provider.retire_responses(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+            command=command,
+        )
+
+        self.assertEqual(retired.response_ids, (response.id,))
+        self.assertEqual(retired.newly_retired_count, 1)
+        self.assertFalse(retired.replayed)
+        self.assertIsNotNone(response.deleted_at)
+        self.assertEqual(len(response.answers), 2)
+        self.assertEqual(
+            response.metadata_["response_retirement"]["idempotency_key"],
+            command.idempotency_key,
+        )
+        self.assertEqual(
+            provider.list_responses(
+                self.session,
+                tenant_id="tenant-1",
+                poll_id=poll.id,
+            ),
+            (),
+        )
+
+        replayed = provider.retire_responses(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+            command=command,
+        )
+        self.assertTrue(replayed.replayed)
+        self.assertEqual(replayed.newly_retired_count, 0)
+        self.assertEqual(replayed.response_ids, (response.id,))
+
+    def test_fully_invalidated_response_is_no_longer_active_or_counted(self) -> None:
+        poll = self._poll()
+        response = submit_poll_response(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+            payload=PollSubmitResponseRequest(
+                respondent_id="person-1",
+                answers=[PollAnswerInput(option_id=poll.options[0].id, value="available")],
+            ),
+        )
+
+        SqlPollSchedulingProvider().update_option(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+            option_id=poll.options[0].id,
+            command=PollOptionUpdateCommand(label="Monday, revised", value={"slot_id": "slot-1"}, metadata={"source": "scheduling"}),
+        )
+
+        self.assertEqual(response.answers, [])
+        self.assertIsNotNone(response.deleted_at)
+        self.assertEqual(
+            SqlPollSchedulingProvider().list_responses(self.session, tenant_id="tenant-1", poll_id=poll.id),
+            (),
+        )
+
+    def test_option_change_is_rejected_when_responses_cannot_be_updated(self) -> None:
+        poll = self._poll(allow_response_update=False)
+        response = self._submit_both(poll, "person-1")
+
+        with self.assertRaisesRegex(PollCapabilityError, "response updates are disabled"):
+            SqlPollSchedulingProvider().update_option(
+                self.session,
+                tenant_id="tenant-1",
+                poll_id=poll.id,
+                option_id=poll.options[0].id,
+                command=PollOptionUpdateCommand(
+                    label="Monday, revised",
+                    value={"slot_id": "slot-1"},
+                    metadata={"source": "scheduling"},
+                ),
+            )
+
+        self.assertEqual(poll.options[0].label, "Monday")
+        self.assertEqual(len(response.answers), 2)
+
+    def test_reorder_preserves_option_identity_and_existing_answers(self) -> None:
+        poll = self._poll(allow_response_update=False)
+        response = self._submit_both(poll, "person-1")
+        first_id, second_id = (option.id for option in poll.options)
+        original_answers = [dict(answer) for answer in response.answers]
+        provider = SqlPollSchedulingProvider()
+
+        reordered = provider.reorder_options(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+            command=PollOptionOrderCommand(option_ids=(second_id, first_id)),
+        )
+
+        self.assertEqual(
+            [(option.id, option.position) for option in reordered.options],
+            [(second_id, 0), (first_id, 1)],
+        )
+        self.assertEqual(response.answers, original_answers)
+        self.assertIsNone(response.deleted_at)
+
+        replayed = provider.reorder_options(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+            command=PollOptionOrderCommand(option_ids=(second_id, first_id)),
+        )
+        self.assertEqual(replayed.options, reordered.options)
+        self.assertEqual(response.answers, original_answers)
+
+    def test_reorder_rejects_partial_or_duplicate_active_option_order(self) -> None:
+        poll = self._poll()
+        first_id, second_id = (option.id for option in poll.options)
+        provider = SqlPollSchedulingProvider()
+
+        with self.assertRaisesRegex(PollCapabilityError, "every active option"):
+            provider.reorder_options(
+                self.session,
+                tenant_id="tenant-1",
+                poll_id=poll.id,
+                command=PollOptionOrderCommand(option_ids=(first_id,)),
+            )
+        with self.assertRaisesRegex(PollCapabilityError, "duplicate"):
+            provider.reorder_options(
+                self.session,
+                tenant_id="tenant-1",
+                poll_id=poll.id,
+                command=PollOptionOrderCommand(option_ids=(first_id, first_id)),
+            )
+
+        self.assertEqual(
+            [(option.id, option.position) for option in poll.options],
+            [(first_id, 0), (second_id, 1)],
+        )
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/test_response_uniqueness.py

@@ -0,0 +1,353 @@
+from __future__ import annotations
+
+import os
+import sqlite3
+import threading
+import unittest
+import uuid
+from concurrent.futures import ThreadPoolExecutor
+from unittest.mock import MagicMock, patch
+
+from sqlalchemy import create_engine, text
+from sqlalchemy.exc import IntegrityError
+from sqlalchemy.orm import Session, sessionmaker
+
+from govoplan_core.db.base import Base, utcnow
+from govoplan_poll.backend import service as poll_service
+from govoplan_poll.backend.db.models import Poll, PollOption, PollResponse
+from govoplan_poll.backend.schemas import (
+    PollAnswerInput,
+    PollCreateRequest,
+    PollOptionInput,
+    PollSubmitResponseRequest,
+)
+from govoplan_poll.backend.service import (
+    PollError,
+    _share_lock_poll_for_response,
+    create_poll,
+    submit_poll_response,
+)
+
+
+class PollResponseUniquenessTests(unittest.TestCase):
+    def setUp(self) -> None:
+        self.engine = create_engine("sqlite:///:memory:")
+        self.tables = [Poll.__table__, PollOption.__table__, PollResponse.__table__]
+        Base.metadata.create_all(self.engine, tables=self.tables)
+        self.Session = sessionmaker(bind=self.engine)
+        self.session: Session = self.Session()
+
+    def tearDown(self) -> None:
+        self.session.close()
+        Base.metadata.drop_all(self.engine, tables=list(reversed(self.tables)))
+        self.engine.dispose()
+
+    def _poll(
+        self,
+        *,
+        allow_anonymous: bool = False,
+        allow_response_update: bool = True,
+    ) -> Poll:
+        return create_poll(
+            self.session,
+            tenant_id="tenant-1",
+            user_id="owner-1",
+            payload=PollCreateRequest(
+                title="One response each",
+                kind="single_choice",
+                status="open",
+                allow_anonymous=allow_anonymous,
+                allow_response_update=allow_response_update,
+                options=[
+                    PollOptionInput(key="yes", label="Yes"),
+                    PollOptionInput(key="no", label="No"),
+                ],
+            ),
+        )
+
+    @staticmethod
+    def _payload(
+        respondent_id: str | None,
+        *,
+        option_key: str = "yes",
+    ) -> PollSubmitResponseRequest:
+        return PollSubmitResponseRequest(
+            respondent_id=respondent_id,
+            respondent_label=respondent_id,
+            answers=[PollAnswerInput(option_key=option_key)],
+        )
+
+    def _hide_first_lookup(self):
+        original = poll_service._existing_response
+        calls = 0
+
+        def hide_once(session, *, poll, respondent_id):
+            nonlocal calls
+            calls += 1
+            if calls == 1:
+                return None
+            return original(
+                session,
+                poll=poll,
+                respondent_id=respondent_id,
+            )
+
+        return patch.object(poll_service, "_existing_response", side_effect=hide_once)
+
+    def test_sqlite_invariant_reconciles_a_racing_insert_to_normal_update(self) -> None:
+        poll = self._poll()
+        winner = submit_poll_response(
+            self.session,
+            tenant_id=poll.tenant_id,
+            poll_id=poll.id,
+            payload=self._payload("person-1"),
+        )
+
+        with self._hide_first_lookup():
+            reconciled = submit_poll_response(
+                self.session,
+                tenant_id=poll.tenant_id,
+                poll_id=poll.id,
+                payload=self._payload("person-1", option_key="no"),
+            )
+
+        self.assertEqual(reconciled.id, winner.id)
+        self.assertEqual(reconciled.answers[0]["option_key"], "no")
+        self.assertEqual(
+            self.session.query(PollResponse)
+            .filter(PollResponse.deleted_at.is_(None))
+            .count(),
+            1,
+        )
+
+    def test_racing_insert_obeys_update_disabled_policy(self) -> None:
+        poll = self._poll()
+        winner = submit_poll_response(
+            self.session,
+            tenant_id=poll.tenant_id,
+            poll_id=poll.id,
+            payload=self._payload("person-1"),
+        )
+        poll.allow_response_update = False
+        self.session.flush()
+
+        with self._hide_first_lookup():
+            with self.assertRaisesRegex(
+                PollError,
+                "Response updates are not allowed",
+            ):
+                submit_poll_response(
+                    self.session,
+                    tenant_id=poll.tenant_id,
+                    poll_id=poll.id,
+                    payload=self._payload("person-1", option_key="no"),
+                )
+
+        self.assertEqual(winner.answers[0]["option_key"], "yes")
+        self.assertEqual(self.session.query(PollResponse).count(), 1)
+
+    def test_anonymous_and_tombstoned_responses_do_not_conflict(self) -> None:
+        poll = self._poll(allow_anonymous=True)
+        anonymous_one = submit_poll_response(
+            self.session,
+            tenant_id=poll.tenant_id,
+            poll_id=poll.id,
+            payload=self._payload(None),
+        )
+        anonymous_two = submit_poll_response(
+            self.session,
+            tenant_id=poll.tenant_id,
+            poll_id=poll.id,
+            payload=self._payload(None, option_key="no"),
+        )
+        identified_one = submit_poll_response(
+            self.session,
+            tenant_id=poll.tenant_id,
+            poll_id=poll.id,
+            payload=self._payload("person-1"),
+        )
+        identified_one.deleted_at = utcnow()
+        self.session.flush()
+        identified_two = submit_poll_response(
+            self.session,
+            tenant_id=poll.tenant_id,
+            poll_id=poll.id,
+            payload=self._payload("person-1", option_key="no"),
+        )
+
+        self.assertNotEqual(anonymous_one.id, anonymous_two.id)
+        self.assertNotEqual(identified_one.id, identified_two.id)
+        self.assertEqual(self.session.query(PollResponse).count(), 4)
+
+    def test_unrelated_integrity_error_is_not_reconciled(self) -> None:
+        poll = self._poll()
+        self.session.execute(
+            text(
+                """
+                CREATE TRIGGER reject_blocked_poll_response
+                BEFORE INSERT ON poll_responses
+                WHEN NEW.respondent_id = 'blocked'
+                BEGIN
+                    SELECT RAISE(ABORT, 'blocked by unrelated invariant');
+                END
+                """
+            )
+        )
+
+        with self.assertRaises(IntegrityError) as caught:
+            submit_poll_response(
+                self.session,
+                tenant_id=poll.tenant_id,
+                poll_id=poll.id,
+                payload=self._payload("blocked"),
+            )
+
+        self.assertIsInstance(caught.exception.orig, sqlite3.IntegrityError)
+        self.assertIn("blocked by unrelated invariant", str(caught.exception.orig))
+
+    def test_response_read_lock_is_shared(self) -> None:
+        session = MagicMock()
+        query = MagicMock()
+        poll = MagicMock()
+        session.query.return_value = query
+        query.filter.return_value = query
+        query.populate_existing.return_value = query
+        query.with_for_update.return_value = query
+        query.first.return_value = poll
+
+        result = _share_lock_poll_for_response(
+            session,
+            tenant_id="tenant-1",
+            poll_id="poll-1",
+        )
+
+        self.assertIs(result, poll)
+        query.with_for_update.assert_called_once_with(read=True)
+
+    def test_orm_mirrors_both_partial_index_predicates(self) -> None:
+        index = next(
+            index
+            for index in PollResponse.__table__.indexes
+            if index.name == "uq_poll_responses_active_respondent"
+        )
+
+        self.assertTrue(index.unique)
+        self.assertEqual(
+            str(index.dialect_options["sqlite"]["where"]),
+            "deleted_at IS NULL AND respondent_id IS NOT NULL",
+        )
+        self.assertEqual(
+            str(index.dialect_options["postgresql"]["where"]),
+            "deleted_at IS NULL AND respondent_id IS NOT NULL",
+        )
+
+
+@unittest.skipUnless(
+    os.environ.get("GOVOPLAN_POLL_TEST_POSTGRES_URL"),
+    "set GOVOPLAN_POLL_TEST_POSTGRES_URL for the two-session PostgreSQL check",
+)
+class PollResponsePostgresConcurrencyTests(unittest.TestCase):
+    def setUp(self) -> None:
+        database_url = os.environ["GOVOPLAN_POLL_TEST_POSTGRES_URL"]
+        self.schema = f"poll_response_race_{uuid.uuid4().hex}"
+        self.admin_engine = create_engine(database_url)
+        with self.admin_engine.begin() as connection:
+            connection.execute(text(f'CREATE SCHEMA "{self.schema}"'))
+        self.engine = create_engine(
+            database_url,
+            connect_args={"options": f"-c search_path={self.schema}"},
+        )
+        self.tables = [Poll.__table__, PollOption.__table__, PollResponse.__table__]
+        Base.metadata.create_all(self.engine, tables=self.tables)
+
+    def tearDown(self) -> None:
+        try:
+            Base.metadata.drop_all(
+                self.engine,
+                tables=list(reversed(self.tables)),
+            )
+        finally:
+            self.engine.dispose()
+            with self.admin_engine.begin() as connection:
+                connection.execute(text(f'DROP SCHEMA "{self.schema}"'))
+            self.admin_engine.dispose()
+
+    def test_two_sessions_converge_on_one_active_response(self) -> None:
+        with Session(self.engine) as session:
+            poll = create_poll(
+                session,
+                tenant_id="tenant-1",
+                user_id="owner-1",
+                payload=PollCreateRequest(
+                    title="Concurrent response",
+                    kind="single_choice",
+                    status="open",
+                    options=[
+                        PollOptionInput(key="yes", label="Yes"),
+                        PollOptionInput(key="no", label="No"),
+                    ],
+                ),
+            )
+            poll_id = poll.id
+            session.commit()
+
+        original = poll_service._existing_response
+        barrier = threading.Barrier(2)
+        thread_state = threading.local()
+
+        def synchronize_first_lookup(session, *, poll, respondent_id):
+            response = original(
+                session,
+                poll=poll,
+                respondent_id=respondent_id,
+            )
+            lookup_count = getattr(thread_state, "lookup_count", 0) + 1
+            thread_state.lookup_count = lookup_count
+            if lookup_count == 1:
+                self.assertIsNone(response)
+                barrier.wait(timeout=10)
+            return response
+
+        def submit(option_key: str) -> str:
+            with Session(self.engine) as session:
+                response = submit_poll_response(
+                    session,
+                    tenant_id="tenant-1",
+                    poll_id=poll_id,
+                    payload=PollSubmitResponseRequest(
+                        respondent_id="person-1",
+                        respondent_label="Person One",
+                        answers=[PollAnswerInput(option_key=option_key)],
+                    ),
+                )
+                response_id = response.id
+                session.commit()
+                return response_id
+
+        with patch.object(
+            poll_service,
+            "_existing_response",
+            side_effect=synchronize_first_lookup,
+        ):
+            with ThreadPoolExecutor(max_workers=2) as executor:
+                response_ids = tuple(
+                    executor.map(submit, ("yes", "no"))
+                )
+
+        self.assertEqual(len(set(response_ids)), 1)
+        with Session(self.engine) as session:
+            active = (
+                session.query(PollResponse)
+                .filter(
+                    PollResponse.poll_id == poll_id,
+                    PollResponse.respondent_id == "person-1",
+                    PollResponse.deleted_at.is_(None),
+                )
+                .all()
+            )
+        self.assertEqual(len(active), 1)
+        self.assertIn(active[0].answers[0]["option_key"], {"yes", "no"})
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/test_service.py

@@ -1,12 +1,15 @@
 from __future__ import annotations
 
 import unittest
+from datetime import datetime, timezone
 
 from sqlalchemy import create_engine
 from sqlalchemy.orm import Session, sessionmaker
 
 from govoplan_core.db.base import Base
-from govoplan_poll.backend.db.models import Poll, PollInvitation, PollOption, PollResponse
+from govoplan_core.core.poll import PollResponseRef, PollResponseSubmissionProvider, PollSchedulingProvider
+from govoplan_poll.backend.capabilities import SqlPollSchedulingProvider
+from govoplan_poll.backend.db.models import Poll, PollInvitation, PollLifecycleTransition, PollOption, PollResponse
 from govoplan_poll.backend.schemas import (
     PollAnswerInput,
     PollCreateRequest,
@@ -19,6 +22,7 @@ from govoplan_poll.backend.service import (
     create_poll,
     create_poll_invitation,
     open_poll,
+    poll_owner_ref,
     poll_result_summary_by_id,
     submit_poll_response,
     submit_poll_response_with_token,
@@ -30,7 +34,13 @@ class PollServiceTests(unittest.TestCase):
         self.engine = create_engine("sqlite:///:memory:")
         Base.metadata.create_all(
             self.engine,
-            tables=[Poll.__table__, PollOption.__table__, PollResponse.__table__, PollInvitation.__table__],
+            tables=[
+                Poll.__table__,
+                PollOption.__table__,
+                PollResponse.__table__,
+                PollInvitation.__table__,
+                PollLifecycleTransition.__table__,
+            ],
         )
         self.Session = sessionmaker(bind=self.engine)
         self.session: Session = self.Session()
@@ -39,10 +49,25 @@ class PollServiceTests(unittest.TestCase):
         self.session.close()
         Base.metadata.drop_all(
             self.engine,
-            tables=[PollInvitation.__table__, PollResponse.__table__, PollOption.__table__, Poll.__table__],
+            tables=[
+                PollLifecycleTransition.__table__,
+                PollInvitation.__table__,
+                PollResponse.__table__,
+                PollOption.__table__,
+                Poll.__table__,
+            ],
         )
         self.engine.dispose()
 
+    def test_response_projection_and_submission_extension_are_backward_compatible(self) -> None:
+        submitted_at = datetime(2026, 7, 20, tzinfo=timezone.utc)
+        legacy_ref = PollResponseRef(None, submitted_at)
+        provider = SqlPollSchedulingProvider()
+
+        self.assertIsNone(legacy_ref.respondent_id)
+        self.assertIsInstance(provider, PollSchedulingProvider)
+        self.assertIsInstance(provider, PollResponseSubmissionProvider)
+
     def test_single_choice_response_can_update_existing_respondent(self) -> None:
         poll = create_poll(
             self.session,
@@ -66,13 +91,24 @@ class PollServiceTests(unittest.TestCase):
             self.session,
             tenant_id="tenant-1",
             poll_id=poll.id,
-            payload=PollSubmitResponseRequest(respondent_id="person-1", answers=[PollAnswerInput(option_key="b")]),
+            payload=PollSubmitResponseRequest(
+                respondent_id="person-1",
+                answers=[PollAnswerInput(option_key="b")],
+                metadata={"invitation_id": 42},
+            ),
         )
         summary = poll_result_summary_by_id(self.session, tenant_id="tenant-1", poll_id=poll.id)
 
         self.assertEqual(first.id, second.id)
         self.assertEqual(summary["response_count"], 1)
         self.assertEqual(summary["leading_option_ids"], [second.answers[0]["option_id"]])
+        response_ref = SqlPollSchedulingProvider().list_responses(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+        )[0]
+        self.assertIsNone(response_ref.invitation_id)
+        self.assertEqual(response_ref.respondent_id, "person-1")
 
     def test_anonymous_response_requires_poll_policy(self) -> None:
         poll = create_poll(
@@ -137,6 +173,11 @@ class PollServiceTests(unittest.TestCase):
                 ],
                 options=[PollOptionInput(key="slot-1", label="Monday")],
             ),
+            mutation_owner=poll_owner_ref(
+                module_id="scheduling",
+                resource_type="scheduling_request",
+                resource_id="request-1",
+            ),
         )
 
         self.assertEqual(poll.context_module, "scheduling")
@@ -267,13 +308,24 @@ class PollServiceTests(unittest.TestCase):
         response = submit_poll_response_with_token(
             self.session,
             token=token,
-            payload=PollSubmitResponseRequest(answers=[PollAnswerInput(option_key="yes")]),
+            payload=PollSubmitResponseRequest(
+                answers=[PollAnswerInput(option_key="yes")],
+                metadata={"invitation_id": "forged-invitation", "client_note": "kept"},
+            ),
         )
 
         self.assertEqual(response.respondent_id, f"invitation:{invitation.id}")
         self.assertEqual(response.respondent_label, "External participant")
         self.assertEqual(response.metadata_["invitation_id"], invitation.id)
+        self.assertEqual(response.metadata_["client_note"], "kept")
         self.assertIsNotNone(invitation.last_used_at)
+        response_ref = SqlPollSchedulingProvider().list_responses(
+            self.session,
+            tenant_id="tenant-1",
+            poll_id=poll.id,
+        )[0]
+        self.assertEqual(response_ref.invitation_id, invitation.id)
+        self.assertEqual(response_ref.respondent_id, f"invitation:{invitation.id}")
 
 
 if __name__ == "__main__":