Implement unified work inbox module

.gitea/workflows/module-package-release.yml

@@ -0,0 +1,270 @@
+name: Module Package Release
+
+on:
+  push:
+    tags:
+      - "v*"
+  workflow_dispatch:
+    inputs:
+      release_tag:
+        description: Existing protected version tag to publish
+        required: true
+        type: string
+
+jobs:
+  publish-packages:
+    runs-on: ubuntu-latest
+    env:
+      GITEA_REPOSITORY: ${{ gitea.repository }}
+    steps:
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5
+        with:
+          fetch-depth: 0
+      - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065
+        with:
+          python-version: "3.12"
+      - uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020
+        with:
+          node-version: "22"
+      - name: Select and validate protected release tag
+        shell: bash
+        env:
+          REQUESTED_TAG: ${{ inputs.release_tag }}
+          TRIGGER_TAG: ${{ gitea.ref_name }}
+        run: |
+          set -euo pipefail
+          tag="${REQUESTED_TAG:-$TRIGGER_TAG}"
+          case "$tag" in
+            v[0-9]*.[0-9]*.[0-9]*) ;;
+            *) echo "Release tag must start with a SemVer-shaped vX.Y.Z value" >&2; exit 1 ;;
+          esac
+          git fetch --force origin "refs/tags/$tag:refs/tags/$tag" refs/heads/main:refs/remotes/origin/main
+          tag_commit="$(git rev-list -n 1 "$tag")"
+          git merge-base --is-ancestor "$tag_commit" refs/remotes/origin/main || {
+            echo "Release tag is not contained in main" >&2
+            exit 1
+          }
+          git checkout --detach "$tag"
+          printf 'RELEASE_TAG=%s\n' "$tag" >> "$GITEA_ENV"
+          printf 'SOURCE_DATE_EPOCH=%s\n' "$(git show -s --format=%ct HEAD)" >> "$GITEA_ENV"
+      - name: Validate package versions
+        run: |
+          python - <<'PY'
+          import json
+          from pathlib import Path
+          import os
+          import re
+          import tomllib
+
+          tag = os.environ["RELEASE_TAG"]
+          expected = tag.removeprefix("v")
+          project = tomllib.loads(Path("pyproject.toml").read_text(encoding="utf-8"))["project"]
+          if project.get("version") != expected:
+              raise SystemExit(f"pyproject version {project.get('version')!r} does not match {tag}")
+          if re.fullmatch(r"govoplan-[a-z0-9-]+", str(project.get("name", ""))) is None:
+              raise SystemExit("Python distribution name must use the govoplan-* namespace")
+          webui = Path("webui/package.json")
+          if webui.is_file():
+              package = json.loads(webui.read_text(encoding="utf-8"))
+              if package.get("version") != expected:
+                  raise SystemExit(f"WebUI version {package.get('version')!r} does not match {tag}")
+              if re.fullmatch(r"@govoplan/[a-z0-9-]+-webui", str(package.get("name", ""))) is None:
+                  raise SystemExit("WebUI package name must use the @govoplan/*-webui namespace")
+              release = Path("webui/package.release.json")
+              if release.is_file():
+                  release_package = json.loads(release.read_text(encoding="utf-8"))
+                  if (
+                      release_package.get("name") != package.get("name")
+                      or release_package.get("version") != expected
+                  ):
+                      raise SystemExit("WebUI release package identity does not match package.json and the release tag")
+          PY
+      - name: Build immutable package artifacts
+        shell: bash
+        run: |
+          set -euo pipefail
+          python -m pip install --disable-pip-version-check build==1.5.0 twine==7.0.0
+          rm -rf dist .package-webui
+          python -m build --wheel --outdir dist
+          python -m twine check dist/*.whl
+          if [[ -f webui/package.json ]]; then
+            mkdir .package-webui
+            cp -a webui/. .package-webui/
+            rm -rf .package-webui/node_modules .package-webui/dist
+            if [[ -f .package-webui/package.release.json ]]; then
+              cp .package-webui/package.release.json .package-webui/package.json
+            fi
+          node <<'NODE'
+          const fs = require("node:fs");
+          const path = ".package-webui/package.json";
+          const packageJson = JSON.parse(fs.readFileSync(path, "utf8"));
+          const groups = ["dependencies", "optionalDependencies", "peerDependencies"];
+          for (const group of groups) {
+            for (const [name, specifier] of Object.entries(packageJson[group] || {})) {
+              if (!name.startsWith("@govoplan/")) continue;
+              if (typeof specifier !== "string") {
+                throw new Error(`${group}.${name} must use a string version`);
+              }
+              const packageSlug = name.slice("@govoplan/".length);
+              if (!packageSlug.endsWith("-webui")) {
+                throw new Error(`${group}.${name} is outside the WebUI package namespace`);
+              }
+              const repository = `govoplan-${packageSlug.slice(0, -"-webui".length)}`;
+              const escapedRepository = repository.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
+              const gitTag = specifier.match(
+                new RegExp(
+                  `^git\\+(?:ssh://git@|https://)git\\.add-ideas\\.de/(?:GovOPlaN|add-ideas)/${escapedRepository}\\.git#v([0-9]+\\.[0-9]+\\.[0-9]+)$`,
+                ),
+              );
+              if (gitTag) {
+                packageJson[group][name] = gitTag[1];
+                continue;
+              }
+              if (specifier.startsWith("file:") || specifier.startsWith("git+")) {
+                throw new Error(
+                  `${group}.${name} must resolve to an exact registry version for publication`,
+                );
+              }
+            }
+          }
+          delete packageJson.private;
+          fs.writeFileSync(path, `${JSON.stringify(packageJson, null, 2)}\n`);
+          NODE
+            npm pkg delete private --prefix .package-webui
+            (cd .package-webui && npm pack --ignore-scripts --pack-destination ../dist)
+          fi
+          python - <<'PY'
+          import hashlib
+          import json
+          from pathlib import Path
+          import os
+          import subprocess
+
+          artifacts = []
+          for path in sorted(Path("dist").iterdir()):
+              if path.suffix not in {".whl", ".tgz"}:
+                  continue
+              digest = hashlib.sha256(path.read_bytes()).hexdigest()
+              artifacts.append({"filename": path.name, "sha256": digest, "size": path.stat().st_size})
+          payload = {
+              "schema_version": "1",
+              "repository": os.environ["GITEA_REPOSITORY"],
+              "tag": os.environ["RELEASE_TAG"],
+              "commit": subprocess.check_output(["git", "rev-parse", "HEAD"], text=True).strip(),
+              "artifacts": artifacts,
+          }
+          Path("dist/package-artifacts.json").write_text(
+              json.dumps(payload, indent=2, sort_keys=True) + "\n",
+              encoding="utf-8",
+          )
+          PY
+      - name: Retain package hash evidence
+        uses: actions/upload-artifact@a8a3f3ad30e3422c9c7b888a15615d19a852ae32
+        with:
+          name: module-packages-${{ gitea.ref_name }}
+          path: dist/package-artifacts.json
+      - name: Check immutable registry state
+        shell: bash
+        env:
+          PACKAGE_TOKEN: ${{ secrets.GOVOPLAN_PACKAGE_TOKEN }}
+        run: |
+          set -euo pipefail
+          test -n "$PACKAGE_TOKEN"
+          python - <<'PY'
+          import hashlib
+          import json
+          import os
+          from pathlib import Path
+          import tomllib
+          from urllib.error import HTTPError
+          from urllib.parse import quote
+          from urllib.request import Request, urlopen
+
+          api_root = "https://git.add-ideas.de/api/v1/packages/GovOPlaN"
+          token = os.environ["PACKAGE_TOKEN"]
+
+          def should_publish(kind, name, version, path):
+              package_url = "/".join(
+                  (api_root, kind, quote(name, safe=""), quote(version, safe=""), "files")
+              )
+              request = Request(
+                  package_url,
+                  headers={"Accept": "application/json", "Authorization": f"token {token}"},
+              )
+              try:
+                  with urlopen(request, timeout=30) as response:
+                      files = json.load(response)
+              except HTTPError as exc:
+                  if exc.code == 404:
+                      print(f"{kind} package {name}=={version} is not published yet")
+                      return True
+                  raise
+              if not isinstance(files, list) or len(files) != 1:
+                  raise SystemExit(
+                      f"immutable {kind} package {name}=={version} has an unexpected file set"
+                  )
+              expected_sha256 = hashlib.sha256(path.read_bytes()).hexdigest()
+              if files[0].get("sha256") != expected_sha256:
+                  raise SystemExit(
+                      f"immutable {kind} package {name}=={version} already exists with a different SHA-256"
+                  )
+              print(f"verified existing {kind} package {name}=={version} ({expected_sha256})")
+              return False
+
+          project = tomllib.loads(Path("pyproject.toml").read_text(encoding="utf-8"))["project"]
+          wheels = tuple(Path("dist").glob("*.whl"))
+          if len(wheels) != 1:
+              raise SystemExit("release build must contain exactly one wheel")
+          publish_pypi = should_publish(
+              "pypi", str(project["name"]), str(project["version"]), wheels[0]
+          )
+
+          tarballs = tuple(Path("dist").glob("*.tgz"))
+          if len(tarballs) > 1:
+              raise SystemExit("release build must contain at most one npm package")
+          publish_npm = False
+          if tarballs:
+              webui = json.loads(
+                  Path(".package-webui/package.json").read_text(encoding="utf-8")
+              )
+              publish_npm = should_publish(
+                  "npm", str(webui["name"]), str(webui["version"]), tarballs[0]
+              )
+
+          with Path(os.environ["GITEA_ENV"]).open("a", encoding="utf-8") as env_file:
+              env_file.write(f"PUBLISH_PYPI={int(publish_pypi)}\n")
+              env_file.write(f"PUBLISH_NPM={int(publish_npm)}\n")
+          PY
+      - name: Publish wheel and WebUI package
+        shell: bash
+        env:
+          PACKAGE_USERNAME: ${{ secrets.GOVOPLAN_PACKAGE_USERNAME }}
+          PACKAGE_TOKEN: ${{ secrets.GOVOPLAN_PACKAGE_TOKEN }}
+        run: |
+          set -euo pipefail
+          test -n "$PACKAGE_USERNAME"
+          test -n "$PACKAGE_TOKEN"
+          if [[ "$PUBLISH_PYPI" == 1 ]]; then
+            TWINE_USERNAME="$PACKAGE_USERNAME" TWINE_PASSWORD="$PACKAGE_TOKEN" \
+              python -m twine upload --non-interactive \
+                --repository-url https://git.add-ideas.de/api/packages/GovOPlaN/pypi \
+                dist/*.whl
+          else
+            echo "Exact wheel is already present; skipping immutable retry."
+          fi
+          shopt -s nullglob
+          webui_packages=(dist/*.tgz)
+          if (( ${#webui_packages[@]} )) && [[ "$PUBLISH_NPM" == 1 ]]; then
+            npmrc="$(mktemp)"
+            trap 'rm -f "$npmrc"' EXIT
+            chmod 600 "$npmrc"
+            printf '%s\n' \
+              '@govoplan:registry=https://git.add-ideas.de/api/packages/GovOPlaN/npm/' \
+              "//git.add-ideas.de/api/packages/GovOPlaN/npm/:_authToken=$PACKAGE_TOKEN" \
+              > "$npmrc"
+            NPM_CONFIG_USERCONFIG="$npmrc" npm publish "./${webui_packages[0]}" \
+              --ignore-scripts --access public \
+              --registry https://git.add-ideas.de/api/packages/GovOPlaN/npm/
+          elif (( ${#webui_packages[@]} )); then
+            echo "Exact WebUI package is already present; skipping immutable retry."
+          fi

README.md

@@ -3,3 +3,10 @@
 <!-- govoplan-repository-type:start -->
 **Repository type:** module (domain).
 <!-- govoplan-repository-type:end -->
+
+GovOPlaN Tasks owns replay-safe explicit work items and presents a unified work
+inbox over module-owned attention items. Workflow Engine keeps process state,
+Notifications keeps delivery state, and each domain module keeps its business
+objects and commands.
+
+See [Tasks Domain And Unified Work Inbox](docs/TASKS_DOMAIN.md).

docs/TASKS_DOMAIN.md

@@ -0,0 +1,65 @@
+# Tasks Domain And Unified Work Inbox
+
+## Boundary
+
+Tasks owns explicit work items, their typed assignments, due dates, priorities,
+state transitions, source references, and the unified work-inbox presentation.
+It does not own the state of a Workflow instance, approval, notification,
+Postbox message, Case, Campaign, record, or any other contributed object.
+
+Modules contribute currently authorized `WorkItem` projections through Core's
+versioned provider-registration contract. The projection links back to the
+source owner, which remains responsible for commands, validation, concurrency,
+audit, retention, and recovery. A failing provider is isolated and shown as an
+unavailable work source; it cannot make other work disappear.
+
+## Explicit Tasks
+
+An explicit task has:
+
+- a tenant and replay-safe idempotency key;
+- title, optional summary, priority, due date, and required action;
+- one or more account, group, role, function, function-assignment, or broad
+  tenant assignments;
+- typed source references and provenance;
+- an optimistic-concurrency revision and immutable transition evidence.
+
+Function assignments are resolved at read time through the optional IDM
+directory. This lets work assigned to an institutional function follow current
+responsibility without turning an incumbent into the permanent owner. When IDM
+is absent, account, group, role, and explicit assignment references continue to
+work; unresolved function work fails closed.
+
+## State And Recovery
+
+Supported states are `open`, `in_progress`, `deferred`, `blocked`, `completed`,
+and `cancelled`. Consequential transitions require a strong `If-Match`
+precondition and compare-and-set the revision. Replaying task creation with the
+same idempotency key returns the same task only when the canonical request is
+identical.
+
+Task changes emit Core change-sequence events so optional Notifications,
+Workflow Engine, Search, Audit, or reporting consumers can react transactionally.
+Database backup and restore is the recovery unit. Domain effects linked from a
+task remain subject to the recovery rules of their owner.
+
+## Permissions
+
+- `tasks:item:read`: discover assigned explicit and contributed work;
+- `tasks:item:write`: create explicit tasks and advance visible task state;
+- `tasks:item:admin`: inspect and recover tenant-wide explicit work.
+
+Current authorization is always rechecked, including for historical or deferred
+work. The inbox never widens the permissions of its sources.
+
+## User And Administrator Guidance
+
+Users open **Work**, filter the current inbox, inspect the responsible source,
+and either open the source-owned action or advance an explicit task. Completed
+and cancelled work is hidden from the default view but remains available through
+the history filter.
+
+Administrators assign the Work participant or Work supervisor role and ensure
+that IDM is enabled when function-bound work is required. Disabling Tasks
+preserves explicit task state. Contributed source work remains with each source
+module and becomes visible again when Tasks is re-enabled.

package.json

@@ -0,0 +1,8 @@
+{
+  "name": "@govoplan/tasks",
+  "version": "0.1.18",
+  "private": true,
+  "description": "Governed work items and unified work inbox for GovOPlaN.",
+  "type": "module",
+  "peerDependencies": {}
+}

pyproject.toml

@@ -0,0 +1,24 @@
+[build-system]
+requires = ["setuptools>=69", "wheel"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "govoplan-tasks"
+version = "0.1.18"
+description = "Governed work items and unified work inbox for GovOPlaN."
+readme = "README.md"
+requires-python = ">=3.12"
+authors = [{ name = "GovOPlaN" }]
+dependencies = [
+  "govoplan-core>=0.1.18",
+  "govoplan-access>=0.1.18",
+]
+
+[tool.setuptools.packages.find]
+where = ["src"]
+
+[tool.setuptools.package-data]
+govoplan_tasks = ["py.typed"]
+
+[project.entry-points."govoplan.modules"]
+tasks = "govoplan_tasks.backend.manifest:get_manifest"

src/govoplan_tasks/__init__.py

@@ -0,0 +1,3 @@
+"""GovOPlaN Tasks module."""
+
+__version__ = "0.1.18"

src/govoplan_tasks/backend/__init__.py

@@ -0,0 +1 @@
+"""Tasks backend."""

src/govoplan_tasks/backend/aggregation.py

@@ -0,0 +1,102 @@
+from __future__ import annotations
+
+import logging
+from dataclasses import dataclass
+from datetime import UTC, datetime
+
+from sqlalchemy.orm import Session
+
+from govoplan_core.auth import ApiPrincipal
+from govoplan_core.core.registry import PlatformRegistry
+from govoplan_core.core.tasks import WorkItem, WorkItemPage, WorkItemQuery
+from govoplan_tasks.backend.schemas import WorkProviderDiagnostic
+
+
+logger = logging.getLogger(__name__)
+
+
+@dataclass(frozen=True, slots=True)
+class WorkAggregation:
+    items: tuple[WorkItem, ...]
+    total: int
+    truncated: bool = False
+    diagnostics: tuple[WorkProviderDiagnostic, ...] = ()
+
+
+def aggregate_work_items(
+    registry: PlatformRegistry,
+    session: Session,
+    principal: ApiPrincipal,
+    *,
+    query: WorkItemQuery,
+) -> WorkAggregation:
+    """Aggregate current work while isolating optional provider failures."""
+
+    items: list[WorkItem] = []
+    total = 0
+    truncated = False
+    diagnostics: list[WorkProviderDiagnostic] = []
+    for registered, provider in registry.work_item_providers():
+        provider_id = registered.registration.id
+        if query.provider_ids and provider_id not in query.provider_ids:
+            continue
+        if query.owner_modules and registered.module_id not in query.owner_modules:
+            continue
+        try:
+            page = provider.list_items(session, principal, query=query)
+            _validate_page(registered.module_id, provider_id, query, page)
+        except Exception:  # provider isolation is part of the aggregation contract
+            logger.exception("Work-item provider failed provider=%s", provider_id)
+            diagnostics.append(
+                WorkProviderDiagnostic(
+                    provider_id=provider_id,
+                    owner_module=registered.module_id,
+                    code="provider_unavailable",
+                    message="This work source is temporarily unavailable.",
+                )
+            )
+            continue
+        items.extend(page.items)
+        total += page.total
+        truncated = truncated or page.truncated
+    items.sort(key=_sort_key)
+    if len(items) > query.limit:
+        truncated = True
+        items = items[: query.limit]
+    return WorkAggregation(
+        items=tuple(items),
+        total=total,
+        truncated=truncated or total > len(items),
+        diagnostics=tuple(diagnostics),
+    )
+
+
+def _validate_page(
+    owner_module: str,
+    provider_id: str,
+    query: WorkItemQuery,
+    page: WorkItemPage,
+) -> None:
+    if len(page.items) > query.limit:
+        raise ValueError("Work-item provider exceeded the requested limit.")
+    for item in page.items:
+        if item.provider_id != provider_id:
+            raise ValueError("Work-item provider returned another provider id.")
+        if item.owner_module != owner_module:
+            raise ValueError("Work-item provider returned another owner module.")
+        if item.tenant_id != query.tenant_id:
+            raise ValueError("Work-item provider returned another tenant.")
+
+
+def _sort_key(item: WorkItem) -> tuple[object, ...]:
+    priorities = {"urgent": 0, "high": 1, "normal": 2, "low": 3}
+    due = _aware(item.due_at) if item.due_at else datetime.max.replace(tzinfo=UTC)
+    updated_rank = -_aware(item.updated_at).timestamp() if item.updated_at else 0.0
+    return (priorities[item.priority], due, updated_rank, item.provider_id, item.id)
+
+
+def _aware(value: datetime) -> datetime:
+    return value.replace(tzinfo=UTC) if value.tzinfo is None else value.astimezone(UTC)
+
+
+__all__ = ["WorkAggregation", "aggregate_work_items"]

src/govoplan_tasks/backend/db/__init__.py

@@ -0,0 +1,3 @@
+from govoplan_tasks.backend.db.models import TaskAssignment, TaskItem
+
+__all__ = ["TaskAssignment", "TaskItem"]

src/govoplan_tasks/backend/db/models.py

@@ -0,0 +1,140 @@
+from __future__ import annotations
+
+import uuid
+from datetime import datetime
+from typing import Any
+
+from sqlalchemy import (
+    DateTime,
+    ForeignKey,
+    Index,
+    Integer,
+    JSON,
+    String,
+    Text,
+    UniqueConstraint,
+)
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+
+from govoplan_core.db.base import Base, TimestampMixin
+
+
+def new_uuid() -> str:
+    return str(uuid.uuid4())
+
+
+class TaskItem(Base, TimestampMixin):
+    __tablename__ = "task_items"
+    __table_args__ = (
+        UniqueConstraint(
+            "tenant_id",
+            "idempotency_key",
+            name="uq_task_item_idempotency",
+        ),
+        Index("ix_task_items_tenant_status", "tenant_id", "status"),
+        Index("ix_task_items_tenant_due", "tenant_id", "due_at", "status"),
+        Index(
+            "ix_task_items_source",
+            "tenant_id",
+            "source_module",
+            "source_resource_type",
+            "source_resource_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)
+    title: Mapped[str] = mapped_column(String(500), nullable=False)
+    summary: Mapped[str | None] = mapped_column(Text, nullable=True)
+    status: Mapped[str] = mapped_column(
+        String(30), nullable=False, default="open", index=True
+    )
+    priority: Mapped[str] = mapped_column(
+        String(20), nullable=False, default="normal", index=True
+    )
+    required_action: Mapped[str | None] = mapped_column(String(500), nullable=True)
+    action_url: Mapped[str | None] = mapped_column(String(1500), nullable=True)
+    due_at: Mapped[datetime | None] = mapped_column(
+        DateTime(timezone=True), nullable=True, index=True
+    )
+    deferred_until: Mapped[datetime | None] = mapped_column(
+        DateTime(timezone=True), nullable=True, index=True
+    )
+    source_module: Mapped[str | None] = mapped_column(
+        String(100), nullable=True, index=True
+    )
+    source_resource_type: Mapped[str | None] = mapped_column(
+        String(100), nullable=True, index=True
+    )
+    source_resource_id: Mapped[str | None] = mapped_column(
+        String(255), nullable=True, index=True
+    )
+    source_revision: Mapped[str | None] = mapped_column(String(255), nullable=True)
+    sources: Mapped[list[dict[str, Any]]] = mapped_column(
+        JSON, default=list, nullable=False
+    )
+    provenance: Mapped[dict[str, Any]] = mapped_column(
+        JSON, default=dict, nullable=False
+    )
+    metadata_: Mapped[dict[str, Any]] = mapped_column(
+        "metadata", JSON, default=dict, nullable=False
+    )
+    revision: Mapped[int] = mapped_column(Integer, nullable=False, default=1)
+    idempotency_key: Mapped[str] = mapped_column(
+        String(255), nullable=False, index=True
+    )
+    request_sha256: Mapped[str] = mapped_column(String(64), nullable=False)
+    created_by: Mapped[str | None] = mapped_column(
+        String(255), nullable=True, index=True
+    )
+    updated_by: Mapped[str | None] = mapped_column(
+        String(255), nullable=True, index=True
+    )
+    completed_at: Mapped[datetime | None] = mapped_column(
+        DateTime(timezone=True), nullable=True
+    )
+    completed_by: Mapped[str | None] = mapped_column(String(255), nullable=True)
+    cancelled_at: Mapped[datetime | None] = mapped_column(
+        DateTime(timezone=True), nullable=True
+    )
+
+    assignments: Mapped[list["TaskAssignment"]] = relationship(
+        back_populates="task",
+        cascade="all, delete-orphan",
+        order_by="TaskAssignment.created_at",
+    )
+
+
+class TaskAssignment(Base, TimestampMixin):
+    __tablename__ = "task_assignments"
+    __table_args__ = (
+        UniqueConstraint(
+            "task_id",
+            "assignment_kind",
+            "assignment_id",
+            name="uq_task_assignment_target",
+        ),
+        Index(
+            "ix_task_assignment_lookup",
+            "tenant_id",
+            "assignment_kind",
+            "assignment_id",
+            "task_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)
+    task_id: Mapped[str] = mapped_column(
+        ForeignKey("task_items.id", ondelete="CASCADE"),
+        nullable=False,
+        index=True,
+    )
+    assignment_kind: Mapped[str] = mapped_column(String(40), nullable=False, index=True)
+    assignment_id: Mapped[str] = mapped_column(String(255), nullable=False, index=True)
+    assignment_label: Mapped[str | None] = mapped_column(String(500), nullable=True)
+
+    task: Mapped[TaskItem] = relationship(back_populates="assignments")
+
+
+__all__ = ["TaskAssignment", "TaskItem", "new_uuid"]

src/govoplan_tasks/backend/manifest.py

@@ -0,0 +1,341 @@
+from __future__ import annotations
+
+from pathlib import Path
+
+from govoplan_core.core.access import (
+    CAPABILITY_AUTH_PERMISSION_EVALUATOR,
+    CAPABILITY_AUTH_PRINCIPAL_RESOLVER,
+)
+from govoplan_core.core.module_guards import (
+    drop_table_retirement_provider,
+    persistent_table_uninstall_guard,
+)
+from govoplan_core.core.modules import (
+    CapabilityDocumentation,
+    DocumentationLink,
+    DocumentationTopic,
+    FrontendModule,
+    FrontendRoute,
+    MigrationSpec,
+    ModuleContext,
+    ModuleInterfaceProvider,
+    ModuleManifest,
+    NavItem,
+    PermissionDefinition,
+    RoleTemplate,
+)
+from govoplan_core.core.provider_governance import declared_module_architecture
+from govoplan_core.core.tasks import (
+    CAPABILITY_TASK_COMMANDS,
+    WorkItemProviderRegistration,
+)
+from govoplan_core.core.views import ViewSurface
+from govoplan_core.db.base import Base
+from govoplan_tasks.backend.db import models as task_models
+from govoplan_tasks.backend.service import SqlTaskService
+
+
+MODULE_ID = "tasks"
+MODULE_NAME = "Tasks"
+MODULE_VERSION = "0.1.18"
+READ_SCOPE = "tasks:item:read"
+WRITE_SCOPE = "tasks:item:write"
+ADMIN_SCOPE = "tasks:item:admin"
+
+
+def _permission(scope: str, label: str, description: str) -> PermissionDefinition:
+    module_id, resource, action = scope.split(":", 2)
+    return PermissionDefinition(
+        scope=scope,
+        label=label,
+        description=description,
+        category="Tasks",
+        level="tenant",
+        module_id=module_id,
+        resource=resource,
+        action=action,
+    )
+
+
+def _router(context: ModuleContext):
+    from govoplan_tasks.backend.router import create_router
+
+    return create_router(context.registry)
+
+
+def _service(context: ModuleContext) -> SqlTaskService:
+    return SqlTaskService(context.registry)
+
+
+def _tenant_summary(session, tenant_id: str) -> dict[str, int]:
+    total = (
+        session.query(task_models.TaskItem)
+        .filter(task_models.TaskItem.tenant_id == tenant_id)
+        .count()
+    )
+    open_items = (
+        session.query(task_models.TaskItem)
+        .filter(
+            task_models.TaskItem.tenant_id == tenant_id,
+            task_models.TaskItem.status.in_(
+                ("open", "in_progress", "deferred", "blocked")
+            ),
+        )
+        .count()
+    )
+    return {"tasks": total, "open_tasks": open_items}
+
+
+PERMISSIONS = (
+    _permission(
+        READ_SCOPE,
+        "View assigned work",
+        "Read explicit and contributed work visible to the current account, group, role, or function.",
+    ),
+    _permission(
+        WRITE_SCOPE,
+        "Manage assigned work",
+        "Create explicit tasks and advance visible task state.",
+    ),
+    _permission(
+        ADMIN_SCOPE,
+        "Administer tenant work",
+        "Read and recover all explicit tasks in the tenant.",
+    ),
+)
+
+ROLE_TEMPLATES = (
+    RoleTemplate(
+        slug="work_participant",
+        name="Work participant",
+        description="Read and advance assigned work and create explicit tasks.",
+        permissions=(READ_SCOPE, WRITE_SCOPE),
+    ),
+    RoleTemplate(
+        slug="work_supervisor",
+        name="Work supervisor",
+        description="Inspect and recover tenant-wide work in addition to participating.",
+        permissions=(READ_SCOPE, WRITE_SCOPE, ADMIN_SCOPE),
+    ),
+)
+
+DOCUMENTATION = (
+    DocumentationTopic(
+        id="tasks.work-inbox",
+        title="Unified work inbox",
+        summary="Resume explicit tasks and module-owned work requiring attention.",
+        body=(
+            "The Work inbox combines explicit Tasks with work contributed by enabled modules. "
+            "Each source keeps ownership of its commands and completion state. Tasks does not turn a "
+            "Workflow handoff, Postbox message, approval, or notification into a copied task. Filters, "
+            "due dates, priorities, and source links help the current actor resume work safely."
+        ),
+        layer="configured",
+        documentation_types=("user", "admin"),
+        audience=("user", "operator", "tenant_admin", "module_admin"),
+        related_modules=(
+            "workflow_engine",
+            "notifications",
+            "postbox",
+            "approvals",
+            "views",
+            "dashboard",
+        ),
+        links=(
+            DocumentationLink(
+                label="Tasks domain",
+                href="govoplan-tasks/docs/TASKS_DOMAIN.md",
+                kind="repository",
+            ),
+        ),
+        translations={
+            "de": {
+                "title": "Gemeinsamer Arbeitsvorrat",
+                "summary": "Explizite Aufgaben und Arbeitsvorgaenge anderer Module sicher fortsetzen.",
+                "body": (
+                    "Der Arbeitsvorrat verbindet explizite Aufgaben mit Arbeitsobjekten aktivierter Module. "
+                    "Jede Quelle behaelt die Verantwortung fuer Befehle und Abschlussstatus. Tasks kopiert "
+                    "keine Workflow-Uebergabe, Postfachnachricht, Freigabe oder Benachrichtigung in einen "
+                    "zweiten Fachzustand. Filter, Fristen, Prioritaeten und Quellverweise helfen beim sicheren Fortsetzen."
+                ),
+            }
+        },
+        metadata={
+            "help_contexts": [
+                "tasks.route.work",
+                "tasks.page.inbox",
+                "tasks.page.detail",
+                "tasks.action.create",
+                "tasks.action.advance",
+                "tasks.field.assignment",
+                "tasks.field.due-at",
+                "tasks.field.priority",
+            ]
+        },
+    ),
+)
+
+manifest = ModuleManifest(
+    id=MODULE_ID,
+    name=MODULE_NAME,
+    version=MODULE_VERSION,
+    dependencies=("access",),
+    optional_dependencies=(
+        "idm",
+        "organizations",
+        "workflow_engine",
+        "workflow",
+        "notifications",
+        "postbox",
+        "approvals",
+        "views",
+        "dashboard",
+        "search",
+    ),
+    required_capabilities=(
+        CAPABILITY_AUTH_PRINCIPAL_RESOLVER,
+        CAPABILITY_AUTH_PERMISSION_EVALUATOR,
+    ),
+    provides_interfaces=(
+        ModuleInterfaceProvider(name=CAPABILITY_TASK_COMMANDS, version="1.0.0"),
+        ModuleInterfaceProvider(name="tasks.work_items", version="1.0.0"),
+    ),
+    permissions=PERMISSIONS,
+    role_templates=ROLE_TEMPLATES,
+    route_factory=_router,
+    nav_items=(
+        NavItem(
+            path="/tasks",
+            label="Work",
+            icon="list-checks",
+            required_any=(READ_SCOPE,),
+            order=21,
+            surface_id="tasks.route.work",
+        ),
+    ),
+    frontend=FrontendModule(
+        module_id=MODULE_ID,
+        package_name="@govoplan/tasks-webui",
+        routes=(
+            FrontendRoute(
+                path="/tasks",
+                component="TasksPage",
+                required_any=(READ_SCOPE,),
+                order=21,
+                surface_id="tasks.route.work",
+            ),
+        ),
+        view_surfaces=(
+            ViewSurface(
+                id="tasks.page.inbox",
+                module_id=MODULE_ID,
+                kind="section",
+                label="Work inbox",
+                parent_id="tasks.route.work",
+                order=20,
+            ),
+            ViewSurface(
+                id="tasks.page.detail",
+                module_id=MODULE_ID,
+                kind="section",
+                label="Work details",
+                parent_id="tasks.route.work",
+                order=30,
+            ),
+            ViewSurface(
+                id="tasks.action.create",
+                module_id=MODULE_ID,
+                kind="action",
+                label="Create task",
+                parent_id="tasks.page.inbox",
+                order=40,
+            ),
+            ViewSurface(
+                id="tasks.action.advance",
+                module_id=MODULE_ID,
+                kind="action",
+                label="Advance task",
+                parent_id="tasks.page.detail",
+                order=50,
+            ),
+            ViewSurface(
+                id="tasks.widget.open-work",
+                module_id=MODULE_ID,
+                kind="section",
+                label="Open work widget",
+                order=60,
+            ),
+        ),
+    ),
+    tenant_summary_providers=(_tenant_summary,),
+    capability_factories={CAPABILITY_TASK_COMMANDS: _service},
+    capability_documentation={
+        CAPABILITY_TASK_COMMANDS: CapabilityDocumentation(
+            label="Task commands",
+            summary="Creates replay-safe explicit tasks without importing the Tasks implementation.",
+            contract_version="1.0.0",
+        )
+    },
+    work_item_providers=(
+        WorkItemProviderRegistration(id="tasks.explicit", factory=_service, order=10),
+    ),
+    migration_spec=MigrationSpec(
+        module_id=MODULE_ID,
+        metadata=Base.metadata,
+        script_location=str(Path(__file__).with_name("migrations") / "versions"),
+        retirement_supported=True,
+        retirement_provider=drop_table_retirement_provider(
+            task_models.TaskAssignment, task_models.TaskItem, label="Tasks"
+        ),
+        retirement_notes="Destructive retirement removes explicit task state after a database snapshot; contributed work remains with its owner.",
+    ),
+    uninstall_guard_providers=(
+        persistent_table_uninstall_guard(
+            task_models.TaskItem, task_models.TaskAssignment, label="Tasks"
+        ),
+    ),
+    documentation=DOCUMENTATION,
+    architecture=declared_module_architecture(
+        layer="human_work_procedure",
+        kind="domain",
+        maturity="vertical_slice",
+        documentation_ref="docs/TASKS_DOMAIN.md",
+        test_ref="tests/test_tasks.py",
+        known_limits=(
+            "Function assignment resolution depends on the optional IDM directory; source-owned inline commands remain deep links in this first slice.",
+        ),
+        supported_authority_modes=("native_authoritative", "linked_reference"),
+        owned_concepts=("explicit task", "task assignment", "unified work inbox"),
+        non_owned_concepts=(
+            "workflow instance",
+            "notification",
+            "postbox message",
+            "approval request",
+            "domain object",
+        ),
+        reference_packages=(
+            "product.service-to-decision",
+            "product.governed-communication",
+            "product.governed-data-assurance",
+        ),
+        migration_docs=("docs/TASKS_DOMAIN.md",),
+        recovery_docs=("docs/TASKS_DOMAIN.md",),
+        security_docs=("docs/TASKS_DOMAIN.md",),
+        operations_docs=("docs/TASKS_DOMAIN.md",),
+    ),
+)
+
+
+def get_manifest() -> ModuleManifest:
+    return manifest
+
+
+__all__ = [
+    "ADMIN_SCOPE",
+    "MODULE_ID",
+    "MODULE_VERSION",
+    "READ_SCOPE",
+    "WRITE_SCOPE",
+    "get_manifest",
+    "manifest",
+]

src/govoplan_tasks/backend/migrations/__init__.py

@@ -0,0 +1 @@
+

src/govoplan_tasks/backend/migrations/versions/7c4d9a2e1f30_v0118_tasks_kernel.py

@@ -0,0 +1,110 @@
+"""v0.1.18 Tasks kernel.
+
+Revision ID: 7c4d9a2e1f30
+Revises: None
+"""
+
+from __future__ import annotations
+
+from alembic import op
+import sqlalchemy as sa
+
+
+revision = "7c4d9a2e1f30"
+down_revision = None
+branch_labels = None
+depends_on = "4f2a9c8e7b6d"
+
+
+def upgrade() -> None:
+    op.create_table(
+        "task_items",
+        sa.Column("id", sa.String(length=36), nullable=False),
+        sa.Column("tenant_id", sa.String(length=36), nullable=False),
+        sa.Column("title", sa.String(length=500), nullable=False),
+        sa.Column("summary", sa.Text(), nullable=True),
+        sa.Column("status", sa.String(length=30), nullable=False),
+        sa.Column("priority", sa.String(length=20), nullable=False),
+        sa.Column("required_action", sa.String(length=500), nullable=True),
+        sa.Column("action_url", sa.String(length=1500), nullable=True),
+        sa.Column("due_at", sa.DateTime(timezone=True), nullable=True),
+        sa.Column("deferred_until", sa.DateTime(timezone=True), nullable=True),
+        sa.Column("source_module", sa.String(length=100), nullable=True),
+        sa.Column("source_resource_type", sa.String(length=100), nullable=True),
+        sa.Column("source_resource_id", sa.String(length=255), nullable=True),
+        sa.Column("source_revision", sa.String(length=255), nullable=True),
+        sa.Column("sources", sa.JSON(), nullable=False),
+        sa.Column("provenance", sa.JSON(), nullable=False),
+        sa.Column("metadata", sa.JSON(), nullable=False),
+        sa.Column("revision", sa.Integer(), nullable=False),
+        sa.Column("idempotency_key", sa.String(length=255), nullable=False),
+        sa.Column("request_sha256", sa.String(length=64), nullable=False),
+        sa.Column("created_by", sa.String(length=255), nullable=True),
+        sa.Column("updated_by", sa.String(length=255), nullable=True),
+        sa.Column("completed_at", sa.DateTime(timezone=True), nullable=True),
+        sa.Column("completed_by", sa.String(length=255), nullable=True),
+        sa.Column("cancelled_at", sa.DateTime(timezone=True), nullable=True),
+        sa.Column("created_at", sa.DateTime(timezone=True), nullable=False),
+        sa.Column("updated_at", sa.DateTime(timezone=True), nullable=False),
+        sa.PrimaryKeyConstraint("id"),
+        sa.UniqueConstraint(
+            "tenant_id", "idempotency_key", name="uq_task_item_idempotency"
+        ),
+    )
+    for column in (
+        "tenant_id",
+        "status",
+        "priority",
+        "due_at",
+        "deferred_until",
+        "source_module",
+        "source_resource_type",
+        "source_resource_id",
+        "idempotency_key",
+        "created_by",
+        "updated_by",
+    ):
+        op.create_index(f"ix_task_items_{column}", "task_items", [column])
+    op.create_index(
+        "ix_task_items_tenant_status", "task_items", ["tenant_id", "status"]
+    )
+    op.create_index(
+        "ix_task_items_tenant_due", "task_items", ["tenant_id", "due_at", "status"]
+    )
+    op.create_index(
+        "ix_task_items_source",
+        "task_items",
+        ["tenant_id", "source_module", "source_resource_type", "source_resource_id"],
+    )
+
+    op.create_table(
+        "task_assignments",
+        sa.Column("id", sa.String(length=36), nullable=False),
+        sa.Column("tenant_id", sa.String(length=36), nullable=False),
+        sa.Column("task_id", sa.String(length=36), nullable=False),
+        sa.Column("assignment_kind", sa.String(length=40), nullable=False),
+        sa.Column("assignment_id", sa.String(length=255), nullable=False),
+        sa.Column("assignment_label", sa.String(length=500), nullable=True),
+        sa.Column("created_at", sa.DateTime(timezone=True), nullable=False),
+        sa.Column("updated_at", sa.DateTime(timezone=True), nullable=False),
+        sa.ForeignKeyConstraint(["task_id"], ["task_items.id"], ondelete="CASCADE"),
+        sa.PrimaryKeyConstraint("id"),
+        sa.UniqueConstraint(
+            "task_id",
+            "assignment_kind",
+            "assignment_id",
+            name="uq_task_assignment_target",
+        ),
+    )
+    for column in ("tenant_id", "task_id", "assignment_kind", "assignment_id"):
+        op.create_index(f"ix_task_assignments_{column}", "task_assignments", [column])
+    op.create_index(
+        "ix_task_assignment_lookup",
+        "task_assignments",
+        ["tenant_id", "assignment_kind", "assignment_id", "task_id"],
+    )
+
+
+def downgrade() -> None:
+    op.drop_table("task_assignments")
+    op.drop_table("task_items")

src/govoplan_tasks/backend/migrations/versions/__init__.py

@@ -0,0 +1 @@
+

src/govoplan_tasks/backend/router.py

@@ -0,0 +1,343 @@
+from __future__ import annotations
+
+from datetime import UTC, datetime
+
+from fastapi import APIRouter, Depends, Header, HTTPException, Query, Response, status
+from sqlalchemy.orm import Session
+
+from govoplan_core.auth import ApiPrincipal, get_api_principal, has_scope
+from govoplan_core.core.concurrency import (
+    ConcurrencyError,
+    MissingPreconditionError,
+    RevisionConflictError,
+    assert_revision_precondition,
+)
+from govoplan_core.core.tasks import (
+    TaskCreateCommand,
+    WorkAssignmentRef,
+    WorkItem,
+    WorkItemQuery,
+    WorkSourceRef,
+)
+from govoplan_core.db.session import get_session
+from govoplan_tasks.backend.aggregation import aggregate_work_items
+from govoplan_tasks.backend.schemas import (
+    TaskActionPayload,
+    TaskCreatePayload,
+    WorkItemListResponse,
+    WorkItemResponse,
+    WorkSummaryResponse,
+)
+from govoplan_tasks.backend.service import (
+    ACTIVE_STATUSES,
+    SqlTaskService,
+    TaskConflict,
+    TaskError,
+    TaskForbidden,
+    TaskNotFound,
+    task_etag,
+)
+
+
+READ_SCOPE = "tasks:item:read"
+WRITE_SCOPE = "tasks:item:write"
+ADMIN_SCOPE = "tasks:item:admin"
+
+
+def create_router(registry: object) -> APIRouter:
+    router = APIRouter(prefix="/tasks", tags=["tasks"])
+    explicit_tasks = SqlTaskService(registry)
+
+    @router.get("", response_model=WorkItemListResponse)
+    def list_work(
+        status_filter: list[str] | None = Query(default=None, alias="status"),
+        priority: list[str] | None = Query(default=None),
+        provider: list[str] | None = Query(default=None),
+        owner_module: list[str] | None = Query(default=None),
+        due_before: datetime | None = Query(default=None),
+        query_text: str = Query(default="", alias="q", max_length=500),
+        limit: int = Query(default=100, ge=1, le=500),
+        session: Session = Depends(get_session),
+        principal: ApiPrincipal = Depends(get_api_principal),
+    ) -> WorkItemListResponse:
+        _require(principal, READ_SCOPE)
+        query = _query(
+            principal,
+            statuses=status_filter,
+            priorities=priority,
+            provider_ids=provider,
+            owner_modules=owner_module,
+            due_before=due_before,
+            text=query_text,
+            limit=limit,
+        )
+        aggregation = aggregate_work_items(
+            registry,
+            session,
+            principal,
+            query=query,
+        )
+        return WorkItemListResponse(
+            items=[_response(item) for item in aggregation.items],
+            total=aggregation.total,
+            truncated=aggregation.truncated,
+            diagnostics=list(aggregation.diagnostics),
+        )
+
+    @router.get("/summary", response_model=WorkSummaryResponse)
+    def work_summary(
+        session: Session = Depends(get_session),
+        principal: ApiPrincipal = Depends(get_api_principal),
+    ) -> WorkSummaryResponse:
+        _require(principal, READ_SCOPE)
+        query = _query(principal, limit=500)
+        aggregation = aggregate_work_items(
+            registry,
+            session,
+            principal,
+            query=query,
+        )
+        now = datetime.now(UTC)
+        return WorkSummaryResponse(
+            total=aggregation.total,
+            open=sum(item.status == "open" for item in aggregation.items),
+            in_progress=sum(item.status == "in_progress" for item in aggregation.items),
+            deferred=sum(item.status == "deferred" for item in aggregation.items),
+            blocked=sum(item.status == "blocked" for item in aggregation.items),
+            overdue=sum(
+                item.due_at is not None
+                and _aware(item.due_at) < now
+                and item.status in ACTIVE_STATUSES
+                for item in aggregation.items
+            ),
+            urgent=sum(item.priority == "urgent" for item in aggregation.items),
+            truncated=aggregation.truncated,
+            diagnostics=list(aggregation.diagnostics),
+        )
+
+    @router.post(
+        "", response_model=WorkItemResponse, status_code=status.HTTP_201_CREATED
+    )
+    def create_task(
+        payload: TaskCreatePayload,
+        response: Response,
+        session: Session = Depends(get_session),
+        principal: ApiPrincipal = Depends(get_api_principal),
+    ) -> WorkItemResponse:
+        _require(principal, WRITE_SCOPE)
+        try:
+            item = explicit_tasks.create_task(
+                session,
+                principal,
+                command=TaskCreateCommand(
+                    tenant_id=principal.tenant_id,
+                    title=payload.title,
+                    summary=payload.summary,
+                    priority=payload.priority,
+                    due_at=payload.due_at,
+                    required_action=payload.required_action,
+                    action_url=payload.action_url,
+                    assignments=tuple(
+                        WorkAssignmentRef(**value.model_dump())
+                        for value in payload.assignments
+                    ),
+                    sources=tuple(
+                        WorkSourceRef(**value.model_dump()) for value in payload.sources
+                    ),
+                    provenance=payload.provenance,
+                    metadata=payload.metadata,
+                    idempotency_key=payload.idempotency_key,
+                ),
+            )
+            session.commit()
+        except (TaskError, ValueError) as exc:
+            session.rollback()
+            raise _task_error(exc) from exc
+        _set_etag(response, item)
+        return _response(item)
+
+    @router.get("/{task_id}", response_model=WorkItemResponse)
+    def get_task(
+        task_id: str,
+        response: Response,
+        session: Session = Depends(get_session),
+        principal: ApiPrincipal = Depends(get_api_principal),
+    ) -> WorkItemResponse:
+        _require(principal, READ_SCOPE)
+        try:
+            row = explicit_tasks.get_task(
+                session,
+                principal,
+                tenant_id=principal.tenant_id,
+                task_id=task_id,
+            )
+            item = explicit_tasks.to_item(row)
+        except TaskError as exc:
+            raise _task_error(exc) from exc
+        _set_etag(response, item)
+        return _response(item)
+
+    @router.post("/{task_id}/actions", response_model=WorkItemResponse)
+    def transition_task(
+        task_id: str,
+        payload: TaskActionPayload,
+        response: Response,
+        if_match: str | None = Header(default=None, alias="If-Match"),
+        session: Session = Depends(get_session),
+        principal: ApiPrincipal = Depends(get_api_principal),
+    ) -> WorkItemResponse:
+        _require_any(principal, WRITE_SCOPE, ADMIN_SCOPE)
+        try:
+            assert_revision_precondition(
+                if_match,
+                resource_type="task",
+                resource_id=task_id,
+                submitted_base_revision=payload.expected_revision,
+            )
+            item = explicit_tasks.transition_task(
+                session,
+                principal,
+                tenant_id=principal.tenant_id,
+                task_id=task_id,
+                action=payload.action,
+                expected_revision=payload.expected_revision,
+                deferred_until=payload.deferred_until,
+                comment=payload.comment,
+            )
+            session.commit()
+        except (TaskError, ConcurrencyError) as exc:
+            session.rollback()
+            raise _mutation_error(exc) from exc
+        _set_etag(response, item)
+        return _response(item)
+
+    return router
+
+
+def _query(
+    principal: ApiPrincipal,
+    *,
+    statuses: list[str] | None = None,
+    priorities: list[str] | None = None,
+    provider_ids: list[str] | None = None,
+    owner_modules: list[str] | None = None,
+    due_before: datetime | None = None,
+    text: str = "",
+    limit: int = 100,
+) -> WorkItemQuery:
+    allowed_statuses = {
+        "open",
+        "in_progress",
+        "deferred",
+        "blocked",
+        "completed",
+        "cancelled",
+    }
+    allowed_priorities = {"low", "normal", "high", "urgent"}
+    normalized_statuses = tuple(statuses or ACTIVE_STATUSES)
+    normalized_priorities = tuple(priorities or ())
+    if any(value not in allowed_statuses for value in normalized_statuses):
+        raise HTTPException(status_code=422, detail="Unsupported task status filter.")
+    if any(value not in allowed_priorities for value in normalized_priorities):
+        raise HTTPException(status_code=422, detail="Unsupported task priority filter.")
+    return WorkItemQuery(
+        tenant_id=principal.tenant_id,
+        statuses=normalized_statuses,  # type: ignore[arg-type]
+        priorities=normalized_priorities,  # type: ignore[arg-type]
+        provider_ids=tuple(provider_ids or ()),
+        owner_modules=tuple(owner_modules or ()),
+        due_before=due_before,
+        text=text,
+        limit=limit,
+    )
+
+
+def _response(item: WorkItem) -> WorkItemResponse:
+    return WorkItemResponse(
+        id=item.id,
+        provider_id=item.provider_id,
+        owner_module=item.owner_module,
+        tenant_id=item.tenant_id,
+        title=item.title,
+        status=item.status,
+        priority=item.priority,
+        summary=item.summary,
+        required_action=item.required_action,
+        action_url=item.action_url,
+        due_at=item.due_at,
+        deferred_until=item.deferred_until,
+        assignments=[
+            {"kind": value.kind, "id": value.id, "label": value.label}
+            for value in item.assignments
+        ],
+        sources=[
+            {
+                "module_id": value.module_id,
+                "resource_type": value.resource_type,
+                "resource_id": value.resource_id,
+                "revision": value.revision,
+                "url": value.url,
+                "label": value.label,
+            }
+            for value in item.sources
+        ],
+        provenance=dict(item.provenance),
+        metadata=dict(item.metadata),
+        revision=item.revision,
+        etag=task_etag(item) if item.provider_id == "tasks.explicit" else None,
+        created_at=item.created_at,
+        updated_at=item.updated_at,
+    )
+
+
+def _aware(value: datetime) -> datetime:
+    return value.replace(tzinfo=UTC) if value.tzinfo is None else value.astimezone(UTC)
+
+
+def _require(principal: ApiPrincipal, scope: str) -> None:
+    if not has_scope(principal, scope):
+        raise HTTPException(status_code=403, detail=f"Missing scope: {scope}")
+
+
+def _require_any(principal: ApiPrincipal, *scopes: str) -> None:
+    if not any(has_scope(principal, scope) for scope in scopes):
+        raise HTTPException(
+            status_code=403, detail=f"Requires one of: {', '.join(scopes)}"
+        )
+
+
+def _task_error(exc: TaskError | ValueError) -> HTTPException:
+    if isinstance(exc, TaskNotFound):
+        code = status.HTTP_404_NOT_FOUND
+    elif isinstance(exc, TaskForbidden):
+        code = status.HTTP_403_FORBIDDEN
+    elif isinstance(exc, TaskConflict):
+        code = status.HTTP_409_CONFLICT
+    else:
+        code = status.HTTP_422_UNPROCESSABLE_CONTENT
+    return HTTPException(
+        status_code=code,
+        detail={"code": getattr(exc, "code", "invalid_task"), "message": str(exc)},
+    )
+
+
+def _mutation_error(exc: TaskError | ConcurrencyError) -> HTTPException:
+    if isinstance(exc, MissingPreconditionError):
+        return HTTPException(status_code=428, detail=exc.as_dict())
+    if isinstance(exc, RevisionConflictError):
+        return HTTPException(status_code=412, detail=exc.as_dict())
+    if isinstance(exc, ConcurrencyError):
+        return HTTPException(
+            status_code=400,
+            detail={"code": "invalid_precondition", "message": str(exc)},
+        )
+    return _task_error(exc)
+
+
+def _set_etag(response: Response, item: WorkItem) -> None:
+    etag = task_etag(item)
+    if etag:
+        response.headers["ETag"] = etag
+
+
+__all__ = ["create_router"]

src/govoplan_tasks/backend/schemas.py

@@ -0,0 +1,118 @@
+from __future__ import annotations
+
+from datetime import datetime
+from typing import Any, Literal
+
+from pydantic import BaseModel, Field, model_validator
+
+
+class WorkAssignmentPayload(BaseModel):
+    kind: Literal[
+        "account",
+        "group",
+        "role",
+        "function",
+        "function_assignment",
+        "anyone",
+    ]
+    id: str = Field(min_length=1, max_length=255)
+    label: str | None = Field(default=None, max_length=500)
+
+
+class WorkSourcePayload(BaseModel):
+    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)
+    revision: str | None = Field(default=None, max_length=255)
+    url: str | None = Field(default=None, max_length=1500)
+    label: str | None = Field(default=None, max_length=500)
+
+
+class WorkItemResponse(BaseModel):
+    id: str
+    provider_id: str
+    owner_module: str
+    tenant_id: str
+    title: str
+    status: str
+    priority: str
+    summary: str | None = None
+    required_action: str | None = None
+    action_url: str | None = None
+    due_at: datetime | None = None
+    deferred_until: datetime | None = None
+    assignments: list[WorkAssignmentPayload] = Field(default_factory=list)
+    sources: list[WorkSourcePayload] = Field(default_factory=list)
+    provenance: dict[str, Any] = Field(default_factory=dict)
+    metadata: dict[str, Any] = Field(default_factory=dict)
+    revision: str
+    etag: str | None = None
+    created_at: datetime | None = None
+    updated_at: datetime | None = None
+
+
+class WorkProviderDiagnostic(BaseModel):
+    provider_id: str
+    owner_module: str
+    code: str
+    message: str
+
+
+class WorkItemListResponse(BaseModel):
+    items: list[WorkItemResponse]
+    total: int
+    truncated: bool = False
+    diagnostics: list[WorkProviderDiagnostic] = Field(default_factory=list)
+
+
+class WorkSummaryResponse(BaseModel):
+    total: int
+    open: int
+    in_progress: int
+    deferred: int
+    blocked: int
+    overdue: int
+    urgent: int
+    truncated: bool = False
+    diagnostics: list[WorkProviderDiagnostic] = Field(default_factory=list)
+
+
+class TaskCreatePayload(BaseModel):
+    title: str = Field(min_length=1, max_length=500)
+    summary: str | None = Field(default=None, max_length=4000)
+    priority: Literal["low", "normal", "high", "urgent"] = "normal"
+    due_at: datetime | None = None
+    required_action: str | None = Field(default=None, max_length=500)
+    action_url: str | None = Field(default=None, max_length=1500)
+    assignments: list[WorkAssignmentPayload] = Field(min_length=1, max_length=100)
+    sources: list[WorkSourcePayload] = Field(default_factory=list, max_length=100)
+    provenance: dict[str, Any] = Field(default_factory=dict)
+    metadata: dict[str, Any] = Field(default_factory=dict)
+    idempotency_key: str = Field(min_length=1, max_length=255)
+
+
+class TaskActionPayload(BaseModel):
+    action: Literal["start", "complete", "defer", "reopen", "cancel"]
+    expected_revision: int = Field(ge=1)
+    deferred_until: datetime | None = None
+    comment: str | None = Field(default=None, max_length=4000)
+
+    @model_validator(mode="after")
+    def validate_action(self) -> "TaskActionPayload":
+        if self.action == "defer" and self.deferred_until is None:
+            raise ValueError("Deferring a task requires a date and time.")
+        if self.action != "defer" and self.deferred_until is not None:
+            raise ValueError("Only a defer action accepts deferred_until.")
+        return self
+
+
+__all__ = [
+    "TaskActionPayload",
+    "TaskCreatePayload",
+    "WorkAssignmentPayload",
+    "WorkItemListResponse",
+    "WorkItemResponse",
+    "WorkProviderDiagnostic",
+    "WorkSourcePayload",
+    "WorkSummaryResponse",
+]

src/govoplan_tasks/backend/service.py

@@ -0,0 +1,516 @@
+from __future__ import annotations
+
+import hashlib
+import json
+from collections.abc import Mapping, Sequence
+from datetime import UTC, datetime
+
+from sqlalchemy import and_, func, or_, select
+from sqlalchemy.orm import Session, selectinload
+
+from govoplan_core.core.change_sequence import record_change
+from govoplan_core.core.concurrency import (
+    RevisionConflictError,
+    claim_revision,
+    strong_resource_etag,
+)
+from govoplan_core.core.idm import CAPABILITY_IDM_DIRECTORY, IdmDirectory
+from govoplan_core.core.tasks import (
+    TaskCreateCommand,
+    WorkAssignmentRef,
+    WorkItem,
+    WorkItemPage,
+    WorkItemQuery,
+    WorkSourceRef,
+)
+from govoplan_tasks.backend.db.models import TaskAssignment, TaskItem
+
+
+READ_SCOPE = "tasks:item:read"
+WRITE_SCOPE = "tasks:item:write"
+ADMIN_SCOPE = "tasks:item:admin"
+PROVIDER_ID = "tasks.explicit"
+ACTIVE_STATUSES = ("open", "in_progress", "deferred", "blocked")
+
+
+class TaskError(RuntimeError):
+    code = "task_error"
+
+
+class TaskNotFound(TaskError):
+    code = "task_not_found"
+
+
+class TaskForbidden(TaskError):
+    code = "task_forbidden"
+
+
+class TaskConflict(TaskError):
+    code = "task_conflict"
+
+
+class SqlTaskService:
+    def __init__(self, registry: object | None = None) -> None:
+        self.registry = registry
+
+    def list_items(
+        self,
+        session: object,
+        principal: object,
+        *,
+        query: WorkItemQuery,
+    ) -> WorkItemPage:
+        if not isinstance(session, Session):
+            raise TypeError("Tasks requires a SQLAlchemy session.")
+        self._require_tenant(principal, query.tenant_id)
+        if not _has(principal, READ_SCOPE) and not _has(principal, ADMIN_SCOPE):
+            raise TaskForbidden("The current principal may not read tasks.")
+        statement = self._visible_statement(principal, query.tenant_id)
+        if query.statuses:
+            statement = statement.where(TaskItem.status.in_(query.statuses))
+        if query.priorities:
+            statement = statement.where(TaskItem.priority.in_(query.priorities))
+        if query.due_before is not None:
+            statement = statement.where(TaskItem.due_at <= query.due_before)
+        if query.text:
+            pattern = f"%{_escape_like(query.text)}%"
+            statement = statement.where(
+                or_(
+                    TaskItem.title.ilike(pattern, escape="\\"),
+                    TaskItem.summary.ilike(pattern, escape="\\"),
+                    TaskItem.required_action.ilike(pattern, escape="\\"),
+                )
+            )
+        count_statement = select(func.count()).select_from(
+            statement.order_by(None).subquery()
+        )
+        total = int(session.scalar(count_statement) or 0)
+        rows = list(
+            session.scalars(
+                statement.order_by(
+                    _priority_rank(),
+                    TaskItem.due_at.is_(None),
+                    TaskItem.due_at.asc(),
+                    TaskItem.updated_at.desc(),
+                    TaskItem.id.desc(),
+                ).limit(query.limit)
+            ).unique()
+        )
+        return WorkItemPage(
+            items=tuple(self.to_item(row) for row in rows),
+            total=total,
+            truncated=total > len(rows),
+        )
+
+    def get_task(
+        self,
+        session: Session,
+        principal: object,
+        *,
+        tenant_id: str,
+        task_id: str,
+        for_update: bool = False,
+    ) -> TaskItem:
+        self._require_tenant(principal, tenant_id)
+        statement = self._visible_statement(principal, tenant_id).where(
+            TaskItem.id == task_id
+        )
+        if for_update:
+            statement = statement.with_for_update()
+        task = session.scalar(statement)
+        if task is None:
+            raise TaskNotFound("Task not found or not visible.")
+        return task
+
+    def create_task(
+        self,
+        session: object,
+        principal: object,
+        *,
+        command: TaskCreateCommand,
+    ) -> WorkItem:
+        if not isinstance(session, Session):
+            raise TypeError("Tasks requires a SQLAlchemy session.")
+        self._require_tenant(principal, command.tenant_id)
+        if not _has(principal, WRITE_SCOPE) and not _has(principal, ADMIN_SCOPE):
+            raise TaskForbidden("The current principal may not create tasks.")
+        digest = _command_digest(command)
+        existing = session.scalar(
+            select(TaskItem)
+            .where(
+                TaskItem.tenant_id == command.tenant_id,
+                TaskItem.idempotency_key == command.idempotency_key,
+            )
+            .options(selectinload(TaskItem.assignments))
+        )
+        if existing is not None:
+            if existing.request_sha256 != digest:
+                raise TaskConflict(
+                    "The idempotency key already identifies a different task request."
+                )
+            return self.to_item(existing)
+
+        sources = [_source_dict(item) for item in command.sources]
+        primary = command.sources[0] if command.sources else None
+        actor_id = _account_id(principal)
+        task = TaskItem(
+            tenant_id=command.tenant_id,
+            title=command.title.strip(),
+            summary=_optional(command.summary),
+            status="open",
+            priority=command.priority,
+            due_at=command.due_at,
+            required_action=_optional(command.required_action),
+            action_url=_optional(command.action_url),
+            source_module=primary.module_id if primary else None,
+            source_resource_type=primary.resource_type if primary else None,
+            source_resource_id=primary.resource_id if primary else None,
+            source_revision=primary.revision if primary else None,
+            sources=sources,
+            provenance=dict(command.provenance),
+            metadata_=dict(command.metadata),
+            idempotency_key=command.idempotency_key.strip(),
+            request_sha256=digest,
+            created_by=actor_id,
+            updated_by=actor_id,
+        )
+        task.assignments = [
+            TaskAssignment(
+                tenant_id=command.tenant_id,
+                assignment_kind=item.kind,
+                assignment_id=item.id,
+                assignment_label=item.label,
+            )
+            for item in _deduplicate_assignments(command.assignments)
+        ]
+        session.add(task)
+        session.flush()
+        record_change(
+            session,
+            module_id="tasks",
+            collection="work_items",
+            resource_type="task",
+            resource_id=task.id,
+            operation="created",
+            tenant_id=task.tenant_id,
+            actor_type="account" if actor_id else None,
+            actor_id=actor_id,
+            payload={
+                "status": task.status,
+                "priority": task.priority,
+                "assignment_count": len(task.assignments),
+                "source_module": task.source_module,
+            },
+        )
+        return self.to_item(task)
+
+    def transition_task(
+        self,
+        session: Session,
+        principal: object,
+        *,
+        tenant_id: str,
+        task_id: str,
+        action: str,
+        expected_revision: int,
+        deferred_until: datetime | None = None,
+        comment: str | None = None,
+    ) -> WorkItem:
+        if not _has(principal, WRITE_SCOPE) and not _has(principal, ADMIN_SCOPE):
+            raise TaskForbidden("The current principal may not update tasks.")
+        task = self.get_task(
+            session,
+            principal,
+            tenant_id=tenant_id,
+            task_id=task_id,
+            for_update=True,
+        )
+        previous_status = task.status
+        next_status = _next_status(task.status, action)
+        if action == "defer":
+            if deferred_until is None or _utc(deferred_until) <= datetime.now(UTC):
+                raise TaskConflict("Deferred tasks require a future date and time.")
+        try:
+            next_revision = claim_revision(
+                session,
+                model=TaskItem,
+                filters=(TaskItem.id == task.id, TaskItem.tenant_id == tenant_id),
+                revision_attribute="revision",
+                expected_revision=expected_revision,
+                resource_type="task",
+                resource_id=task.id,
+                refresh_path=f"/api/v1/tasks/{task.id}",
+            )
+        except RevisionConflictError:
+            raise
+        session.refresh(task)
+        actor_id = _account_id(principal)
+        now = datetime.now(UTC)
+        task.revision = next_revision
+        task.status = next_status
+        task.updated_by = actor_id
+        task.deferred_until = _utc(deferred_until) if action == "defer" else None
+        if action == "complete":
+            task.completed_at = now
+            task.completed_by = actor_id
+        elif action == "reopen":
+            task.completed_at = None
+            task.completed_by = None
+            task.cancelled_at = None
+        elif action == "cancel":
+            task.cancelled_at = now
+        metadata = dict(task.metadata_ or {})
+        history = list(metadata.get("transition_history") or [])
+        history.append(
+            {
+                "action": action,
+                "from_status": previous_status,
+                "to_status": next_status,
+                "actor_id": actor_id,
+                "recorded_at": now.isoformat(),
+                "comment": _optional(comment),
+            }
+        )
+        metadata["transition_history"] = history[-100:]
+        task.metadata_ = metadata
+        session.flush()
+        record_change(
+            session,
+            module_id="tasks",
+            collection="work_items",
+            resource_type="task",
+            resource_id=task.id,
+            operation="updated",
+            tenant_id=tenant_id,
+            actor_type="account" if actor_id else None,
+            actor_id=actor_id,
+            payload={
+                "action": action,
+                "status": next_status,
+                "revision": next_revision,
+            },
+        )
+        return self.to_item(task)
+
+    def _visible_statement(self, principal: object, tenant_id: str):
+        statement = (
+            select(TaskItem)
+            .where(TaskItem.tenant_id == tenant_id)
+            .options(selectinload(TaskItem.assignments))
+        )
+        if _has(principal, ADMIN_SCOPE):
+            return statement
+        targets = self._assignment_targets(principal, tenant_id)
+        conditions = [
+            and_(
+                TaskAssignment.assignment_kind == kind,
+                TaskAssignment.assignment_id.in_(tuple(ids)),
+            )
+            for kind, ids in targets.items()
+            if ids
+        ]
+        if not conditions:
+            return statement.where(False)
+        return statement.join(TaskAssignment).where(or_(*conditions)).distinct()
+
+    def _assignment_targets(
+        self, principal: object, tenant_id: str
+    ) -> dict[str, set[str]]:
+        targets = {
+            "account": {_account_id(principal)} if _account_id(principal) else set(),
+            "group": set(getattr(principal, "group_ids", ()) or ()),
+            "role": set(getattr(principal, "role_ids", ()) or ()),
+            "function_assignment": set(
+                getattr(principal, "function_assignment_ids", ()) or ()
+            ),
+            "function": set(),
+            "anyone": {"*"},
+        }
+        directory = self._idm_directory()
+        if directory is not None and _account_id(principal):
+            assignments = directory.organization_function_assignments_for_account(
+                _account_id(principal),
+                tenant_id=tenant_id,
+            )
+            targets["function"].update(
+                item.function_id
+                for item in assignments
+                if item.status == "active" and item.tenant_id == tenant_id
+            )
+        return targets
+
+    def _idm_directory(self) -> IdmDirectory | None:
+        registry = self.registry
+        if (
+            registry is None
+            or not hasattr(registry, "has_capability")
+            or not registry.has_capability(CAPABILITY_IDM_DIRECTORY)
+        ):
+            return None
+        provider = registry.capability(CAPABILITY_IDM_DIRECTORY)
+        return provider if isinstance(provider, IdmDirectory) else None
+
+    @staticmethod
+    def _require_tenant(principal: object, tenant_id: str) -> None:
+        if str(getattr(principal, "tenant_id", "") or "") != tenant_id:
+            raise TaskForbidden("Task access is limited to the active tenant.")
+
+    @staticmethod
+    def to_item(task: TaskItem) -> WorkItem:
+        return WorkItem(
+            id=task.id,
+            provider_id=PROVIDER_ID,
+            owner_module="tasks",
+            tenant_id=task.tenant_id,
+            title=task.title,
+            summary=task.summary,
+            status=task.status,  # type: ignore[arg-type]
+            priority=task.priority,  # type: ignore[arg-type]
+            required_action=task.required_action,
+            action_url=task.action_url,
+            due_at=task.due_at,
+            deferred_until=task.deferred_until,
+            assignments=tuple(
+                WorkAssignmentRef(
+                    kind=item.assignment_kind,  # type: ignore[arg-type]
+                    id=item.assignment_id,
+                    label=item.assignment_label,
+                )
+                for item in task.assignments
+            ),
+            sources=tuple(WorkSourceRef(**item) for item in task.sources),
+            provenance=dict(task.provenance or {}),
+            metadata=dict(task.metadata_ or {}),
+            revision=str(task.revision),
+            created_at=task.created_at,
+            updated_at=task.updated_at,
+        )
+
+
+def task_etag(task: WorkItem) -> str | None:
+    try:
+        return strong_resource_etag("task", task.id, int(task.revision))
+    except (TypeError, ValueError):
+        return None
+
+
+def _has(principal: object, scope: str) -> bool:
+    checker = getattr(principal, "has", None)
+    return bool(callable(checker) and checker(scope))
+
+
+def _account_id(principal: object) -> str:
+    return str(getattr(principal, "account_id", "") or "")
+
+
+def _optional(value: str | None) -> str | None:
+    normalized = str(value or "").strip()
+    return normalized or None
+
+
+def _utc(value: datetime) -> datetime:
+    if value.tzinfo is None:
+        return value.replace(tzinfo=UTC)
+    return value.astimezone(UTC)
+
+
+def _source_dict(value: WorkSourceRef) -> dict[str, str | None]:
+    return {
+        "module_id": value.module_id,
+        "resource_type": value.resource_type,
+        "resource_id": value.resource_id,
+        "revision": value.revision,
+        "url": value.url,
+        "label": value.label,
+    }
+
+
+def _deduplicate_assignments(
+    assignments: Sequence[WorkAssignmentRef],
+) -> tuple[WorkAssignmentRef, ...]:
+    by_key: dict[tuple[str, str], WorkAssignmentRef] = {}
+    for item in assignments:
+        by_key.setdefault((item.kind, item.id), item)
+    return tuple(by_key.values())
+
+
+def _command_digest(command: TaskCreateCommand) -> str:
+    payload = {
+        "tenant_id": command.tenant_id,
+        "title": command.title.strip(),
+        "summary": _optional(command.summary),
+        "priority": command.priority,
+        "due_at": command.due_at.isoformat() if command.due_at else None,
+        "required_action": _optional(command.required_action),
+        "action_url": _optional(command.action_url),
+        "assignments": [
+            {"kind": item.kind, "id": item.id, "label": item.label}
+            for item in _deduplicate_assignments(command.assignments)
+        ],
+        "sources": [_source_dict(item) for item in command.sources],
+        "provenance": dict(command.provenance),
+        "metadata": dict(command.metadata),
+    }
+    encoded = json.dumps(payload, sort_keys=True, separators=(",", ":"), default=str)
+    return hashlib.sha256(encoded.encode("utf-8")).hexdigest()
+
+
+def _next_status(current: str, action: str) -> str:
+    allowed: Mapping[str, Mapping[str, str]] = {
+        "open": {
+            "start": "in_progress",
+            "complete": "completed",
+            "defer": "deferred",
+            "cancel": "cancelled",
+        },
+        "in_progress": {
+            "complete": "completed",
+            "defer": "deferred",
+            "cancel": "cancelled",
+        },
+        "deferred": {
+            "start": "in_progress",
+            "complete": "completed",
+            "reopen": "open",
+            "cancel": "cancelled",
+        },
+        "blocked": {
+            "reopen": "open",
+            "cancel": "cancelled",
+        },
+        "completed": {"reopen": "open"},
+        "cancelled": {"reopen": "open"},
+    }
+    next_status = allowed.get(current, {}).get(action)
+    if next_status is None:
+        raise TaskConflict(
+            f"Action {action!r} is not available for a {current!r} task."
+        )
+    return next_status
+
+
+def _escape_like(value: str) -> str:
+    return value.replace("\\", "\\\\").replace("%", "\\%").replace("_", "\\_")
+
+
+def _priority_rank():
+    from sqlalchemy import case
+
+    return case(
+        (TaskItem.priority == "urgent", 0),
+        (TaskItem.priority == "high", 1),
+        (TaskItem.priority == "normal", 2),
+        else_=3,
+    )
+
+
+__all__ = [
+    "ACTIVE_STATUSES",
+    "PROVIDER_ID",
+    "SqlTaskService",
+    "TaskConflict",
+    "TaskError",
+    "TaskForbidden",
+    "TaskNotFound",
+    "task_etag",
+]

src/govoplan_tasks/py.typed

@@ -0,0 +1 @@
+

tests/__init__.py

@@ -0,0 +1 @@
+

tests/test_migrations.py

@@ -0,0 +1,41 @@
+from __future__ import annotations
+
+from pathlib import Path
+import tempfile
+import unittest
+
+from alembic.runtime.migration import MigrationContext
+from sqlalchemy import create_engine, inspect
+
+from govoplan_access.backend.manifest import get_manifest as get_access_manifest
+from govoplan_core.db.migrations import migrate_database
+from govoplan_tasks.backend.manifest import get_manifest as get_tasks_manifest
+
+
+class TasksMigrationTests(unittest.TestCase):
+    def test_fresh_migration_creates_task_kernel_and_head(self) -> None:
+        with tempfile.TemporaryDirectory(prefix="govoplan-tasks-migration-") as directory:
+            url = f"sqlite:///{Path(directory) / 'tasks.db'}"
+            migrate_database(
+                database_url=url,
+                enabled_modules=("access", "tasks"),
+                manifest_factories=(get_access_manifest, get_tasks_manifest),
+            )
+            engine = create_engine(url)
+            try:
+                self.assertTrue(
+                    {"task_items", "task_assignments"}.issubset(
+                        inspect(engine).get_table_names()
+                    )
+                )
+                with engine.connect() as connection:
+                    self.assertIn(
+                        "7c4d9a2e1f30",
+                        set(MigrationContext.configure(connection).get_current_heads()),
+                    )
+            finally:
+                engine.dispose()
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/test_tasks.py

@@ -0,0 +1,293 @@
+from __future__ import annotations
+
+import unittest
+from datetime import UTC, datetime, timedelta
+from types import SimpleNamespace
+
+from sqlalchemy import create_engine, select
+from sqlalchemy.orm import sessionmaker
+
+from govoplan_core.auth import ApiPrincipal
+from govoplan_core.core.access import PrincipalRef
+from govoplan_core.core.change_sequence import ChangeSequenceEntry
+from govoplan_core.core.concurrency import RevisionConflictError
+from govoplan_core.core.tasks import (
+    TaskCreateCommand,
+    WorkAssignmentRef,
+    WorkItemQuery,
+    WorkSourceRef,
+)
+from govoplan_core.db.base import Base
+from govoplan_tasks.backend.db.models import TaskAssignment, TaskItem
+from govoplan_tasks.backend.manifest import get_manifest
+from govoplan_tasks.backend.service import (
+    ADMIN_SCOPE,
+    READ_SCOPE,
+    WRITE_SCOPE,
+    SqlTaskService,
+    TaskConflict,
+    TaskForbidden,
+    TaskNotFound,
+)
+
+
+class TaskServiceTests(unittest.TestCase):
+    def setUp(self) -> None:
+        self.engine = create_engine("sqlite:///:memory:")
+        self.tables = (
+            ChangeSequenceEntry.__table__,
+            TaskItem.__table__,
+            TaskAssignment.__table__,
+        )
+        Base.metadata.create_all(self.engine, tables=self.tables)
+        self.Session = sessionmaker(bind=self.engine)
+        self.service = SqlTaskService()
+
+    def tearDown(self) -> None:
+        Base.metadata.drop_all(self.engine, tables=reversed(self.tables))
+        self.engine.dispose()
+
+    @staticmethod
+    def principal(
+        account_id: str,
+        *,
+        tenant_id: str = "tenant-1",
+        scopes: set[str] | None = None,
+        group_ids: set[str] | None = None,
+        role_ids: set[str] | None = None,
+        function_assignment_ids: set[str] | None = None,
+    ) -> ApiPrincipal:
+        return ApiPrincipal(
+            principal=PrincipalRef(
+                account_id=account_id,
+                membership_id=f"membership-{account_id}",
+                tenant_id=tenant_id,
+                scopes=frozenset(
+                    {READ_SCOPE, WRITE_SCOPE} if scopes is None else scopes
+                ),
+                group_ids=frozenset(group_ids or ()),
+                role_ids=frozenset(role_ids or ()),
+                function_assignment_ids=frozenset(function_assignment_ids or ()),
+            ),
+            account=SimpleNamespace(id=account_id),
+            user=SimpleNamespace(id=f"membership-{account_id}"),
+        )
+
+    @staticmethod
+    def command(
+        *,
+        idempotency_key: str = "request-1",
+        title: str = "Review the submission",
+        assignments: tuple[WorkAssignmentRef, ...] | None = None,
+    ) -> TaskCreateCommand:
+        return TaskCreateCommand(
+            tenant_id="tenant-1",
+            title=title,
+            summary="Resolve the governed handoff.",
+            priority="high",
+            due_at=datetime.now(UTC) + timedelta(days=2),
+            required_action="Review and decide",
+            action_url="/cases/case-1",
+            assignments=assignments
+            or (WorkAssignmentRef(kind="account", id="account-1"),),
+            sources=(
+                WorkSourceRef(
+                    module_id="cases",
+                    resource_type="case",
+                    resource_id="case-1",
+                    revision="3",
+                    url="/cases/case-1",
+                ),
+            ),
+            provenance={"workflow_instance_id": "workflow-1"},
+            idempotency_key=idempotency_key,
+        )
+
+    def test_replayed_create_is_idempotent_and_mismatch_is_rejected(self) -> None:
+        principal = self.principal("account-1")
+        with self.Session() as session:
+            command = self.command()
+            first = self.service.create_task(session, principal, command=command)
+            replay = self.service.create_task(session, principal, command=command)
+            self.assertEqual(first.id, replay.id)
+            self.assertEqual(1, len(session.scalars(select(TaskItem)).all()))
+            self.assertEqual(
+                1,
+                len(session.scalars(select(ChangeSequenceEntry)).all()),
+            )
+
+            with self.assertRaises(TaskConflict):
+                self.service.create_task(
+                    session,
+                    principal,
+                    command=self.command(title="A different task"),
+                )
+
+    def test_visibility_uses_typed_assignments_and_fails_closed(self) -> None:
+        creator = self.principal(
+            "account-1",
+            scopes={READ_SCOPE, WRITE_SCOPE, ADMIN_SCOPE},
+        )
+        with self.Session() as session:
+            account_task = self.service.create_task(
+                session,
+                creator,
+                command=self.command(idempotency_key="account"),
+            )
+            group_task = self.service.create_task(
+                session,
+                creator,
+                command=self.command(
+                    idempotency_key="group",
+                    assignments=(WorkAssignmentRef(kind="group", id="group-1"),),
+                ),
+            )
+            function_assignment_task = self.service.create_task(
+                session,
+                creator,
+                command=self.command(
+                    idempotency_key="function-assignment",
+                    assignments=(
+                        WorkAssignmentRef(
+                            kind="function_assignment",
+                            id="assignment-1",
+                        ),
+                    ),
+                ),
+            )
+            session.flush()
+
+            group_reader = self.principal(
+                "account-2",
+                group_ids={"group-1"},
+                function_assignment_ids={"assignment-1"},
+            )
+            page = self.service.list_items(
+                session,
+                group_reader,
+                query=WorkItemQuery(tenant_id="tenant-1"),
+            )
+            self.assertEqual(
+                {group_task.id, function_assignment_task.id},
+                {item.id for item in page.items},
+            )
+            self.assertNotIn(account_task.id, {item.id for item in page.items})
+
+            hidden = self.principal("account-3")
+            empty = self.service.list_items(
+                session,
+                hidden,
+                query=WorkItemQuery(tenant_id="tenant-1"),
+            )
+            self.assertEqual(0, empty.total)
+
+    def test_admin_can_read_all_tenant_work_but_not_another_tenant(self) -> None:
+        admin = self.principal(
+            "admin",
+            scopes={READ_SCOPE, WRITE_SCOPE, ADMIN_SCOPE},
+        )
+        with self.Session() as session:
+            task = self.service.create_task(
+                session,
+                admin,
+                command=self.command(
+                    assignments=(WorkAssignmentRef(kind="account", id="someone-else"),),
+                ),
+            )
+            page = self.service.list_items(
+                session,
+                admin,
+                query=WorkItemQuery(tenant_id="tenant-1"),
+            )
+            self.assertEqual([task.id], [item.id for item in page.items])
+
+            with self.assertRaises(TaskForbidden):
+                self.service.list_items(
+                    session,
+                    admin,
+                    query=WorkItemQuery(tenant_id="tenant-2"),
+                )
+
+    def test_capability_enforces_read_and_write_scopes(self) -> None:
+        without_scopes = self.principal("account-1", scopes=set())
+        with self.Session() as session:
+            with self.assertRaises(TaskForbidden):
+                self.service.create_task(
+                    session,
+                    without_scopes,
+                    command=self.command(),
+                )
+            with self.assertRaises(TaskForbidden):
+                self.service.list_items(
+                    session,
+                    without_scopes,
+                    query=WorkItemQuery(tenant_id="tenant-1"),
+                )
+
+    def test_transition_uses_revision_and_records_exact_history(self) -> None:
+        principal = self.principal("account-1")
+        with self.Session() as session:
+            created = self.service.create_task(
+                session,
+                principal,
+                command=self.command(),
+            )
+            started = self.service.transition_task(
+                session,
+                principal,
+                tenant_id="tenant-1",
+                task_id=created.id,
+                action="start",
+                expected_revision=1,
+                comment="Taking responsibility",
+            )
+            self.assertEqual("in_progress", started.status)
+            self.assertEqual("2", started.revision)
+            history = started.metadata["transition_history"]
+            self.assertEqual("open", history[0]["from_status"])
+            self.assertEqual("in_progress", history[0]["to_status"])
+
+            with self.assertRaises(RevisionConflictError):
+                self.service.transition_task(
+                    session,
+                    principal,
+                    tenant_id="tenant-1",
+                    task_id=created.id,
+                    action="complete",
+                    expected_revision=1,
+                )
+
+    def test_invalid_transition_and_hidden_task_are_indistinguishable(self) -> None:
+        owner = self.principal("account-1")
+        other = self.principal("account-2")
+        with self.Session() as session:
+            task = self.service.create_task(session, owner, command=self.command())
+            with self.assertRaises(TaskConflict):
+                self.service.transition_task(
+                    session,
+                    owner,
+                    tenant_id="tenant-1",
+                    task_id=task.id,
+                    action="reopen",
+                    expected_revision=1,
+                )
+            with self.assertRaises(TaskNotFound):
+                self.service.get_task(
+                    session,
+                    other,
+                    tenant_id="tenant-1",
+                    task_id=task.id,
+                )
+
+
+class TaskManifestTests(unittest.TestCase):
+    def test_manifest_exposes_static_docs_and_work_provider(self) -> None:
+        manifest = get_manifest()
+        self.assertEqual("tasks", manifest.id)
+        self.assertEqual("tasks.explicit", manifest.work_item_providers[0].id)
+        self.assertTrue(manifest.documentation)
+        self.assertEqual("@govoplan/tasks-webui", manifest.frontend.package_name)
+
+
+if __name__ == "__main__":
+    unittest.main()

webui/package.json

@@ -0,0 +1,28 @@
+{
+  "name": "@govoplan/tasks-webui",
+  "version": "0.1.18",
+  "private": true,
+  "type": "module",
+  "main": "src/index.ts",
+  "module": "src/index.ts",
+  "types": "src/index.ts",
+  "exports": {
+    ".": {
+      "types": "./src/index.ts",
+      "import": "./src/index.ts"
+    },
+    "./styles/tasks.css": "./src/styles/tasks.css"
+  },
+  "peerDependencies": {
+    "@govoplan/core-webui": "^0.1.18",
+    "lucide-react": "^1.23.0",
+    "react": ">=19.2.7 <20",
+    "react-dom": ">=19.2.7 <20",
+    "react-router": ">=8.3.0 <9"
+  },
+  "peerDependenciesMeta": {
+    "@govoplan/core-webui": {
+      "optional": true
+    }
+  }
+}

webui/src/api/tasks.ts

@@ -0,0 +1,146 @@
+import { apiFetch, type ApiSettings } from "@govoplan/core-webui";
+
+export type WorkStatus =
+  | "open"
+  | "in_progress"
+  | "deferred"
+  | "blocked"
+  | "completed"
+  | "cancelled";
+
+export type WorkPriority = "low" | "normal" | "high" | "urgent";
+
+export type WorkAssignment = {
+  kind: "account" | "group" | "role" | "function" | "function_assignment" | "anyone";
+  id: string;
+  label?: string | null;
+};
+
+export type WorkSource = {
+  module_id: string;
+  resource_type: string;
+  resource_id: string;
+  revision?: string | null;
+  url?: string | null;
+  label?: string | null;
+};
+
+export type WorkItem = {
+  id: string;
+  provider_id: string;
+  owner_module: string;
+  tenant_id: string;
+  title: string;
+  status: WorkStatus;
+  priority: WorkPriority;
+  summary?: string | null;
+  required_action?: string | null;
+  action_url?: string | null;
+  due_at?: string | null;
+  deferred_until?: string | null;
+  assignments: WorkAssignment[];
+  sources: WorkSource[];
+  provenance: Record<string, unknown>;
+  metadata: Record<string, unknown>;
+  revision: string;
+  etag?: string | null;
+  created_at?: string | null;
+  updated_at?: string | null;
+};
+
+export type WorkProviderDiagnostic = {
+  provider_id: string;
+  owner_module: string;
+  code: string;
+  message: string;
+};
+
+export type WorkListResponse = {
+  items: WorkItem[];
+  total: number;
+  truncated: boolean;
+  diagnostics: WorkProviderDiagnostic[];
+};
+
+export type WorkSummary = {
+  total: number;
+  open: number;
+  in_progress: number;
+  deferred: number;
+  blocked: number;
+  overdue: number;
+  urgent: number;
+  truncated: boolean;
+  diagnostics: WorkProviderDiagnostic[];
+};
+
+export type TaskCreatePayload = {
+  title: string;
+  summary?: string | null;
+  priority: WorkPriority;
+  due_at?: string | null;
+  required_action?: string | null;
+  action_url?: string | null;
+  assignments: WorkAssignment[];
+  sources?: WorkSource[];
+  provenance?: Record<string, unknown>;
+  metadata?: Record<string, unknown>;
+  idempotency_key: string;
+};
+
+export function listWork(
+  settings: ApiSettings,
+  filters: {
+    statuses?: WorkStatus[];
+    priorities?: WorkPriority[];
+    providers?: string[];
+    modules?: string[];
+    q?: string;
+    limit?: number;
+  } = {}
+): Promise<WorkListResponse> {
+  const params = new URLSearchParams();
+  filters.statuses?.forEach((value) => params.append("status", value));
+  filters.priorities?.forEach((value) => params.append("priority", value));
+  filters.providers?.forEach((value) => params.append("provider", value));
+  filters.modules?.forEach((value) => params.append("owner_module", value));
+  if (filters.q) params.set("q", filters.q);
+  if (filters.limit) params.set("limit", String(filters.limit));
+  const query = params.toString();
+  return apiFetch<WorkListResponse>(
+    settings,
+    `/api/v1/tasks${query ? `?${query}` : ""}`
+  );
+}
+
+export function loadWorkSummary(settings: ApiSettings): Promise<WorkSummary> {
+  return apiFetch<WorkSummary>(settings, "/api/v1/tasks/summary");
+}
+
+export function createTask(
+  settings: ApiSettings,
+  payload: TaskCreatePayload
+): Promise<WorkItem> {
+  return apiFetch<WorkItem>(settings, "/api/v1/tasks", {
+    method: "POST",
+    body: JSON.stringify(payload)
+  });
+}
+
+export function transitionTask(
+  settings: ApiSettings,
+  task: WorkItem,
+  action: "start" | "complete" | "defer" | "reopen" | "cancel",
+  deferredUntil?: string | null
+): Promise<WorkItem> {
+  if (!task.etag) throw new Error("i18n:govoplan-tasks.reason.refresh_required");
+  return apiFetch<WorkItem>(settings, `/api/v1/tasks/${task.id}/actions`, {
+    method: "POST",
+    headers: { "If-Match": task.etag },
+    body: JSON.stringify({
+      action,
+      expected_revision: Number(task.revision),
+      deferred_until: deferredUntil || null
+    })
+  });
+}

webui/src/features/tasks/TasksPage.tsx

@@ -0,0 +1,385 @@
+import { useEffect, useMemo, useState, type FormEvent } from "react";
+import {
+  CalendarClock,
+  Check,
+  CirclePlay,
+  ExternalLink,
+  ListChecks,
+  Plus,
+  RefreshCw,
+  RotateCcw,
+  Search,
+  XCircle
+} from "lucide-react";
+import { Link } from "react-router";
+import {
+  AdminIconButton,
+  Button,
+  DateTimeField,
+  Dialog,
+  DismissibleAlert,
+  DocumentationHelpLink,
+  FormField,
+  SegmentedControl,
+  SelectionList,
+  SelectionListItem,
+  StatusBadge,
+  hasScope,
+  type ApiSettings,
+  type AuthInfo
+} from "@govoplan/core-webui";
+import {
+  createTask,
+  listWork,
+  transitionTask,
+  type TaskCreatePayload,
+  type WorkItem,
+  type WorkPriority,
+  type WorkStatus
+} from "../../api/tasks";
+
+type StatusView = "active" | "completed" | "all";
+
+const ACTIVE_STATUSES: WorkStatus[] = ["open", "in_progress", "deferred", "blocked"];
+const CLOSED_STATUSES: WorkStatus[] = ["completed", "cancelled"];
+const ALL_STATUSES: WorkStatus[] = [...ACTIVE_STATUSES, ...CLOSED_STATUSES];
+const DOCUMENTATION = {
+  contextId: "tasks.page.inbox",
+  topicId: "tasks.work-inbox",
+  documentationType: "user" as const
+};
+
+export default function TasksPage({ settings, auth }: { settings: ApiSettings; auth: AuthInfo }) {
+  const [items, setItems] = useState<WorkItem[]>([]);
+  const [selectedKey, setSelectedKey] = useState("");
+  const [statusView, setStatusView] = useState<StatusView>("active");
+  const [searchDraft, setSearchDraft] = useState("");
+  const [query, setQuery] = useState("");
+  const [loading, setLoading] = useState(true);
+  const [busy, setBusy] = useState(false);
+  const [error, setError] = useState("");
+  const [diagnostics, setDiagnostics] = useState<string[]>([]);
+  const [createOpen, setCreateOpen] = useState(false);
+  const [deferOpen, setDeferOpen] = useState(false);
+  const [deferredUntil, setDeferredUntil] = useState("");
+
+  const canWrite = hasScope(auth, "tasks:item:write");
+  const selected = useMemo(
+    () => items.find((item) => workKey(item) === selectedKey) ?? items[0] ?? null,
+    [items, selectedKey]
+  );
+
+  useEffect(() => {
+    void load();
+  }, [settings.apiBaseUrl, settings.apiKey, settings.accessToken, statusView, query]);
+
+  async function load() {
+    setLoading(true);
+    setError("");
+    try {
+      const response = await listWork(settings, {
+        statuses: statusView === "active" ? ACTIVE_STATUSES : statusView === "completed" ? CLOSED_STATUSES : ALL_STATUSES,
+        q: query,
+        limit: 500
+      });
+      setItems(response.items);
+      setDiagnostics(response.diagnostics.map((item) => `${item.owner_module}: ${item.message}`));
+      setSelectedKey((current) => response.items.some((item) => workKey(item) === current) ? current : response.items[0] ? workKey(response.items[0]) : "");
+    } catch (reason) {
+      setError(errorMessage(reason));
+    } finally {
+      setLoading(false);
+    }
+  }
+
+  async function runAction(action: "start" | "complete" | "defer" | "reopen" | "cancel") {
+    if (!selected || selected.provider_id !== "tasks.explicit") return;
+    setBusy(true);
+    setError("");
+    try {
+      const next = await transitionTask(
+        settings,
+        selected,
+        action,
+        action === "defer" ? localDateTimeToIso(deferredUntil) : null
+      );
+      setItems((current) => current.map((item) => item.id === next.id ? next : item));
+      setDeferOpen(false);
+      setDeferredUntil("");
+      await load();
+    } catch (reason) {
+      setError(errorMessage(reason));
+    } finally {
+      setBusy(false);
+    }
+  }
+
+  function submitSearch(event: FormEvent) {
+    event.preventDefault();
+    setQuery(searchDraft.trim());
+  }
+
+  return (
+    <main className="tasks-page" data-help-context-id="tasks.page.inbox">
+      <div className="tasks-shell">
+        <aside className="tasks-sidebar">
+          <div className="tasks-sidebar-bar">
+            <span className="tasks-title"><ListChecks size={18} /><strong>i18n:govoplan-tasks.work</strong></span>
+            <span className="tasks-toolbar-actions">
+              <AdminIconButton
+                label="i18n:govoplan-tasks.refresh"
+                icon={<RefreshCw size={16} aria-hidden="true" />}
+                onClick={() => void load()}
+                disabled={loading || busy}
+              />
+              {canWrite ? (
+                <AdminIconButton
+                  label="i18n:govoplan-tasks.create_task"
+                  icon={<Plus size={16} aria-hidden="true" />}
+                  onClick={() => setCreateOpen(true)}
+                  disabled={busy}
+                  helpContextId="tasks.action.create"
+                />
+              ) : null}
+            </span>
+          </div>
+          <form className="tasks-search" onSubmit={submitSearch} role="search">
+            <Search size={15} aria-hidden="true" />
+            <input
+              value={searchDraft}
+              onChange={(event) => setSearchDraft(event.target.value)}
+              placeholder="i18n:govoplan-tasks.search_placeholder"
+              aria-label="i18n:govoplan-tasks.search"
+            />
+          </form>
+          <SegmentedControl
+            className="tasks-status-filter"
+            options={[
+              { id: "active", label: "i18n:govoplan-tasks.active" },
+              { id: "completed", label: "i18n:govoplan-tasks.completed" },
+              { id: "all", label: "i18n:govoplan-tasks.all" }
+            ]}
+            value={statusView}
+            onChange={setStatusView}
+            ariaLabel="i18n:govoplan-tasks.status_filter"
+            width="fill"
+          />
+          <div className="tasks-list">
+            {loading ? <p className="tasks-note">i18n:govoplan-tasks.loading</p> : null}
+            {!loading && items.length === 0 ? <p className="tasks-note">i18n:govoplan-tasks.empty</p> : null}
+            {items.length ? (
+              <SelectionList label="i18n:govoplan-tasks.work_items">
+                {items.map((item) => (
+                  <SelectionListItem
+                    key={`${item.provider_id}:${item.id}`}
+                    selected={selected ? workKey(selected) === workKey(item) : false}
+                    onClick={() => setSelectedKey(workKey(item))}
+                    className="tasks-list-item"
+                  >
+                    <span className="tasks-list-heading"><strong>{item.title}</strong><StatusBadge status={item.status} label={statusLabel(item.status)} /></span>
+                    <span className="tasks-list-meta"><span>{moduleLabel(item.owner_module)}</span><span>{dueLabel(item.due_at)}</span></span>
+                  </SelectionListItem>
+                ))}
+              </SelectionList>
+            ) : null}
+          </div>
+        </aside>
+
+        <section className="tasks-workspace" data-help-context-id="tasks.page.detail">
+          <div className="tasks-topbar">
+            <span className="tasks-detail-title"><ListChecks size={18} /><strong>{selected?.title ?? "i18n:govoplan-tasks.work_details"}</strong></span>
+            <span className="tasks-toolbar-actions">
+              <DocumentationHelpLink reference={DOCUMENTATION} />
+              {selected?.provider_id === "tasks.explicit" && canWrite ? <TaskActions item={selected} busy={busy} onAction={(action) => action === "defer" ? setDeferOpen(true) : void runAction(action)} /> : null}
+            </span>
+          </div>
+
+          {error ? <DismissibleAlert tone="danger" compact resetKey={error}>{error}</DismissibleAlert> : null}
+          {diagnostics.map((message) => <DismissibleAlert key={message} tone="warning" compact resetKey={message}>{message}</DismissibleAlert>)}
+
+          {selected ? <TaskDetails item={selected} /> : (
+            <div className="tasks-empty-detail"><ListChecks size={24} /><h1>i18n:govoplan-tasks.work</h1><p>i18n:govoplan-tasks.select_help</p></div>
+          )}
+        </section>
+      </div>
+
+      <CreateTaskDialog
+        open={createOpen}
+        busy={busy}
+        settings={settings}
+        auth={auth}
+        onClose={() => setCreateOpen(false)}
+        onCreated={async (item) => {
+          setCreateOpen(false);
+          setSelectedKey(workKey(item));
+          await load();
+        }}
+        onError={setError}
+        setBusy={setBusy}
+      />
+      <Dialog
+        open={deferOpen}
+        title="i18n:govoplan-tasks.defer_task"
+        onClose={() => setDeferOpen(false)}
+        closeDisabled={busy}
+        portal
+        helpContextId="tasks.action.advance"
+        footer={<><Button onClick={() => setDeferOpen(false)} disabled={busy}>i18n:govoplan-tasks.cancel</Button><Button variant="primary" onClick={() => void runAction("defer")} disabled={!deferredUntil || busy}>i18n:govoplan-tasks.defer</Button></>}
+      >
+        <FormField label="i18n:govoplan-tasks.resume_at" helpContextId="tasks.field.due-at">
+          <DateTimeField value={deferredUntil} onChange={setDeferredUntil} min={localDateTime(new Date())} />
+        </FormField>
+      </Dialog>
+    </main>
+  );
+}
+
+function TaskActions({ item, busy, onAction }: { item: WorkItem; busy: boolean; onAction: (action: "start" | "complete" | "defer" | "reopen" | "cancel") => void }) {
+  if (["completed", "cancelled"].includes(item.status)) {
+    return <Button onClick={() => onAction("reopen")} disabled={busy}><RotateCcw size={15} /> i18n:govoplan-tasks.reopen</Button>;
+  }
+  return (
+    <>
+      {["open", "deferred"].includes(item.status) ? <Button onClick={() => onAction("start")} disabled={busy}><CirclePlay size={15} /> i18n:govoplan-tasks.start</Button> : null}
+      <Button variant="primary" onClick={() => onAction("complete")} disabled={busy}><Check size={15} /> i18n:govoplan-tasks.complete</Button>
+      <Button onClick={() => onAction("defer")} disabled={busy}><CalendarClock size={15} /> i18n:govoplan-tasks.defer</Button>
+      <Button variant="danger" onClick={() => onAction("cancel")} disabled={busy}><XCircle size={15} /> i18n:govoplan-tasks.cancel_task</Button>
+    </>
+  );
+}
+
+function TaskDetails({ item }: { item: WorkItem }) {
+  const safeAction = safeActionUrl(item.action_url);
+  return (
+    <div className="tasks-detail">
+      <section className="tasks-detail-main">
+        <div className="tasks-detail-meta"><StatusBadge status={item.status} label={statusLabel(item.status)} /><StatusBadge status={item.priority} label={priorityLabel(item.priority)} /><span>{moduleLabel(item.owner_module)}</span>{item.due_at ? <span>{dueLabel(item.due_at)}</span> : null}</div>
+        <h1>{item.title}</h1>
+        {item.summary ? <p>{item.summary}</p> : null}
+        {item.required_action ? <div className="tasks-required-action"><strong>i18n:govoplan-tasks.required_action</strong><span>{item.required_action}</span></div> : null}
+        {safeAction ? <Link className="btn btn-primary tasks-open-action" to={safeAction}><ExternalLink size={16} /> i18n:govoplan-tasks.open_work</Link> : null}
+      </section>
+      <section className="tasks-properties">
+        <h2>i18n:govoplan-tasks.context</h2>
+        <dl>
+          <div><dt>i18n:govoplan-tasks.source_module</dt><dd>{moduleLabel(item.owner_module)}</dd></div>
+          <div><dt>i18n:govoplan-tasks.provider</dt><dd>{item.provider_id}</dd></div>
+          <div><dt>i18n:govoplan-tasks.assigned_to</dt><dd>{item.assignments.map(assignmentLabel).join(", ") || "i18n:govoplan-tasks.not_set"}</dd></div>
+          <div><dt>i18n:govoplan-tasks.updated</dt><dd>{formatDate(item.updated_at)}</dd></div>
+        </dl>
+      </section>
+      {item.sources.length ? <section className="tasks-sources"><h2>i18n:govoplan-tasks.sources</h2>{item.sources.map((source) => <div key={`${source.module_id}:${source.resource_type}:${source.resource_id}`} className="tasks-source"><strong>{source.label || `${source.resource_type} ${source.resource_id}`}</strong><span>{moduleLabel(source.module_id)}{source.revision ? ` · ${source.revision}` : ""}</span></div>)}</section> : null}
+    </div>
+  );
+}
+
+function CreateTaskDialog({ open, busy, settings, auth, onClose, onCreated, onError, setBusy }: { open: boolean; busy: boolean; settings: ApiSettings; auth: AuthInfo; onClose: () => void; onCreated: (item: WorkItem) => Promise<void>; onError: (message: string) => void; setBusy: (value: boolean) => void }) {
+  const [title, setTitle] = useState("");
+  const [summary, setSummary] = useState("");
+  const [requiredAction, setRequiredAction] = useState("");
+  const [priority, setPriority] = useState<WorkPriority>("normal");
+  const [dueAt, setDueAt] = useState("");
+  const accountId = auth.principal?.account_id || auth.user.account_id;
+
+  async function submit(event: FormEvent) {
+    event.preventDefault();
+    if (!title.trim() || !accountId) return;
+    setBusy(true);
+    onError("");
+    const payload: TaskCreatePayload = {
+      title: title.trim(),
+      summary: summary.trim() || null,
+      required_action: requiredAction.trim() || null,
+      priority,
+      due_at: dueAt ? localDateTimeToIso(dueAt) : null,
+      assignments: [{ kind: "account", id: accountId, label: auth.user.display_name || auth.user.email }],
+      idempotency_key: crypto.randomUUID()
+    };
+    try {
+      const item = await createTask(settings, payload);
+      setTitle("");
+      setSummary("");
+      setRequiredAction("");
+      setPriority("normal");
+      setDueAt("");
+      await onCreated(item);
+    } catch (reason) {
+      onError(errorMessage(reason));
+    } finally {
+      setBusy(false);
+    }
+  }
+
+  return (
+    <Dialog
+      open={open}
+      title="i18n:govoplan-tasks.create_task"
+      onClose={onClose}
+      closeDisabled={busy}
+      portal
+      helpContextId="tasks.action.create"
+      footer={<><Button onClick={onClose} disabled={busy}>i18n:govoplan-tasks.cancel</Button><Button type="submit" form="tasks-create-form" variant="primary" disabled={!title.trim() || !accountId || busy}>i18n:govoplan-tasks.create</Button></>}
+    >
+      <form id="tasks-create-form" className="tasks-create-form" onSubmit={submit}>
+        <FormField label="i18n:govoplan-tasks.title"><input value={title} onChange={(event) => setTitle(event.target.value)} maxLength={500} autoFocus required /></FormField>
+        <FormField label="i18n:govoplan-tasks.summary"><textarea value={summary} onChange={(event) => setSummary(event.target.value)} maxLength={4000} rows={4} /></FormField>
+        <div className="tasks-create-grid">
+          <FormField label="i18n:govoplan-tasks.priority" helpContextId="tasks.field.priority"><select value={priority} onChange={(event) => setPriority(event.target.value as WorkPriority)}><option value="low">i18n:govoplan-tasks.priority.low</option><option value="normal">i18n:govoplan-tasks.priority.normal</option><option value="high">i18n:govoplan-tasks.priority.high</option><option value="urgent">i18n:govoplan-tasks.priority.urgent</option></select></FormField>
+          <FormField label="i18n:govoplan-tasks.due_at" helpContextId="tasks.field.due-at"><DateTimeField value={dueAt} onChange={setDueAt} min={localDateTime(new Date())} /></FormField>
+        </div>
+        <FormField label="i18n:govoplan-tasks.required_action"><input value={requiredAction} onChange={(event) => setRequiredAction(event.target.value)} maxLength={500} /></FormField>
+        <p className="tasks-assignment-note">i18n:govoplan-tasks.assigned_to_you</p>
+      </form>
+    </Dialog>
+  );
+}
+
+function safeActionUrl(value?: string | null): string | null {
+  if (!value || !value.startsWith("/") || value.startsWith("//") || value.includes("\\")) return null;
+  return value;
+}
+
+function workKey(item: WorkItem): string {
+  return `${item.provider_id}:${item.id}`;
+}
+
+function assignmentLabel(value: WorkItem["assignments"][number]): string {
+  return value.label || `${value.kind}: ${value.id}`;
+}
+
+function statusLabel(value: string): string {
+  return `i18n:govoplan-tasks.status.${value}`;
+}
+
+function priorityLabel(value: string): string {
+  return `i18n:govoplan-tasks.priority.${value}`;
+}
+
+function moduleLabel(value: string): string {
+  return value.replaceAll("_", " ").replace(/\b\w/g, (letter) => letter.toUpperCase());
+}
+
+function dueLabel(value?: string | null): string {
+  if (!value) return "i18n:govoplan-tasks.no_due_date";
+  return formatDate(value);
+}
+
+function formatDate(value?: string | null): string {
+  if (!value) return "i18n:govoplan-tasks.not_set";
+  const parsed = new Date(value);
+  if (Number.isNaN(parsed.getTime())) return value;
+  return new Intl.DateTimeFormat(undefined, { dateStyle: "medium", timeStyle: "short" }).format(parsed);
+}
+
+function localDateTime(value: Date): string {
+  const shifted = new Date(value.getTime() - value.getTimezoneOffset() * 60_000);
+  return shifted.toISOString().slice(0, 16);
+}
+
+function localDateTimeToIso(value: string): string {
+  return new Date(value).toISOString();
+}
+
+function errorMessage(reason: unknown): string {
+  return reason instanceof Error ? reason.message : "i18n:govoplan-tasks.request_failed";
+}

webui/src/features/tasks/TasksSummaryWidget.tsx

@@ -0,0 +1,46 @@
+import { useEffect, useState } from "react";
+import { Link } from "react-router";
+import {
+  DismissibleAlert,
+  LoadingFrame,
+  MetricCard,
+  type ApiSettings
+} from "@govoplan/core-webui";
+import { loadWorkSummary, type WorkSummary } from "../../api/tasks";
+
+export default function TasksSummaryWidget({ settings, refreshKey }: { settings: ApiSettings; refreshKey: number }) {
+  const [summary, setSummary] = useState<WorkSummary | null>(null);
+  const [loading, setLoading] = useState(true);
+  const [error, setError] = useState("");
+
+  useEffect(() => {
+    let active = true;
+    setLoading(true);
+    void loadWorkSummary(settings)
+      .then((value) => {
+        if (active) {
+          setSummary(value);
+          setError("");
+        }
+      })
+      .catch((reason: unknown) => {
+        if (active) setError(reason instanceof Error ? reason.message : "i18n:govoplan-tasks.request_failed");
+      })
+      .finally(() => {
+        if (active) setLoading(false);
+      });
+    return () => { active = false; };
+  }, [settings.apiBaseUrl, settings.apiKey, settings.accessToken, refreshKey]);
+
+  return (
+    <LoadingFrame loading={loading} label="i18n:govoplan-tasks.loading_summary">
+      {error ? <DismissibleAlert tone="warning" resetKey={error}>{error}</DismissibleAlert> : null}
+      <div className="metric-grid inside dashboard-widget-metrics">
+        <MetricCard label="i18n:govoplan-tasks.open" value={(summary?.open ?? 0) + (summary?.in_progress ?? 0)} tone="info" detail="i18n:govoplan-tasks.actionable_work" />
+        <MetricCard label="i18n:govoplan-tasks.overdue" value={summary?.overdue ?? 0} tone={summary?.overdue ? "danger" : "good"} detail="i18n:govoplan-tasks.due_date_passed" />
+        <MetricCard label="i18n:govoplan-tasks.blocked" value={summary?.blocked ?? 0} tone={summary?.blocked ? "warning" : "good"} detail="i18n:govoplan-tasks.needs_resolution" />
+      </div>
+      <div className="tasks-widget-actions"><Link className="btn btn-secondary" to="/tasks">i18n:govoplan-tasks.open_work_inbox</Link></div>
+    </LoadingFrame>
+  );
+}

webui/src/i18n/generatedTranslations.ts

@@ -0,0 +1,134 @@
+import type { PlatformTranslations } from "@govoplan/core-webui";
+
+export const generatedTranslations: PlatformTranslations = {
+  de: {
+    "i18n:govoplan-tasks.work": "Arbeit",
+    "i18n:govoplan-tasks.work_inbox": "Arbeitsvorrat",
+    "i18n:govoplan-tasks.work_details": "Arbeitsdetails",
+    "i18n:govoplan-tasks.work_items": "Arbeitsobjekte",
+    "i18n:govoplan-tasks.work_category": "Arbeit und Verfahren",
+    "i18n:govoplan-tasks.widget": "Widget für offene Arbeit",
+    "i18n:govoplan-tasks.widget_description": "Zugewiesene, überfällige und blockierte Arbeit aus aktivierten Modulen.",
+    "i18n:govoplan-tasks.refresh": "Arbeitsvorrat aktualisieren",
+    "i18n:govoplan-tasks.create_task": "Aufgabe erstellen",
+    "i18n:govoplan-tasks.create": "Erstellen",
+    "i18n:govoplan-tasks.search": "Arbeitsvorrat durchsuchen",
+    "i18n:govoplan-tasks.search_placeholder": "Titel, Beschreibung oder erforderliche Aktion",
+    "i18n:govoplan-tasks.status_filter": "Statusfilter",
+    "i18n:govoplan-tasks.active": "Aktiv",
+    "i18n:govoplan-tasks.completed": "Abgeschlossen",
+    "i18n:govoplan-tasks.all": "Alle",
+    "i18n:govoplan-tasks.loading": "Arbeitsvorrat wird geladen.",
+    "i18n:govoplan-tasks.empty": "In dieser Ansicht ist keine Arbeit vorhanden.",
+    "i18n:govoplan-tasks.select_help": "Wählen Sie ein Arbeitsobjekt, um Kontext, Zuständigkeit und nächste Aktion zu prüfen.",
+    "i18n:govoplan-tasks.start": "Beginnen",
+    "i18n:govoplan-tasks.complete": "Abschließen",
+    "i18n:govoplan-tasks.defer": "Zurückstellen",
+    "i18n:govoplan-tasks.defer_task": "Aufgabe zurückstellen",
+    "i18n:govoplan-tasks.reopen": "Wieder öffnen",
+    "i18n:govoplan-tasks.cancel": "Abbrechen",
+    "i18n:govoplan-tasks.cancel_task": "Aufgabe abbrechen",
+    "i18n:govoplan-tasks.advance_task": "Aufgabenstatus fortschreiben",
+    "i18n:govoplan-tasks.resume_at": "Wieder vorlegen am",
+    "i18n:govoplan-tasks.title": "Titel",
+    "i18n:govoplan-tasks.summary": "Beschreibung",
+    "i18n:govoplan-tasks.priority": "Priorität",
+    "i18n:govoplan-tasks.due_at": "Fällig am",
+    "i18n:govoplan-tasks.required_action": "Erforderliche Aktion",
+    "i18n:govoplan-tasks.assigned_to_you": "Die Aufgabe wird Ihnen zugewiesen. Weitere Zuständigkeitsarten stehen über angebundene Verfahren und die API zur Verfügung.",
+    "i18n:govoplan-tasks.open_work": "Arbeit fortsetzen",
+    "i18n:govoplan-tasks.context": "Kontext und Zuständigkeit",
+    "i18n:govoplan-tasks.source_module": "Quellmodul",
+    "i18n:govoplan-tasks.provider": "Quelle des Arbeitsobjekts",
+    "i18n:govoplan-tasks.assigned_to": "Zugewiesen an",
+    "i18n:govoplan-tasks.updated": "Aktualisiert",
+    "i18n:govoplan-tasks.sources": "Verknüpfte Quellen",
+    "i18n:govoplan-tasks.not_set": "Nicht festgelegt",
+    "i18n:govoplan-tasks.no_due_date": "Ohne Frist",
+    "i18n:govoplan-tasks.request_failed": "Der Arbeitsvorrat konnte nicht verarbeitet werden.",
+    "i18n:govoplan-tasks.reason.refresh_required": "Die Aufgabe muss vor der Änderung aktualisiert werden.",
+    "i18n:govoplan-tasks.loading_summary": "Arbeitsübersicht wird geladen",
+    "i18n:govoplan-tasks.open": "Offen",
+    "i18n:govoplan-tasks.overdue": "Überfällig",
+    "i18n:govoplan-tasks.blocked": "Blockiert",
+    "i18n:govoplan-tasks.actionable_work": "Offen oder in Bearbeitung",
+    "i18n:govoplan-tasks.due_date_passed": "Frist ist überschritten",
+    "i18n:govoplan-tasks.needs_resolution": "Hindernis muss geklärt werden",
+    "i18n:govoplan-tasks.open_work_inbox": "Arbeitsvorrat öffnen",
+    "i18n:govoplan-tasks.status.open": "Offen",
+    "i18n:govoplan-tasks.status.in_progress": "In Bearbeitung",
+    "i18n:govoplan-tasks.status.deferred": "Zurückgestellt",
+    "i18n:govoplan-tasks.status.blocked": "Blockiert",
+    "i18n:govoplan-tasks.status.completed": "Abgeschlossen",
+    "i18n:govoplan-tasks.status.cancelled": "Abgebrochen",
+    "i18n:govoplan-tasks.priority.low": "Niedrig",
+    "i18n:govoplan-tasks.priority.normal": "Normal",
+    "i18n:govoplan-tasks.priority.high": "Hoch",
+    "i18n:govoplan-tasks.priority.urgent": "Dringend"
+  },
+  en: {
+    "i18n:govoplan-tasks.work": "Work",
+    "i18n:govoplan-tasks.work_inbox": "Work inbox",
+    "i18n:govoplan-tasks.work_details": "Work details",
+    "i18n:govoplan-tasks.work_items": "Work items",
+    "i18n:govoplan-tasks.work_category": "Work and procedures",
+    "i18n:govoplan-tasks.widget": "Open work widget",
+    "i18n:govoplan-tasks.widget_description": "Assigned, overdue, and blocked work from enabled modules.",
+    "i18n:govoplan-tasks.refresh": "Refresh work inbox",
+    "i18n:govoplan-tasks.create_task": "Create task",
+    "i18n:govoplan-tasks.create": "Create",
+    "i18n:govoplan-tasks.search": "Search work inbox",
+    "i18n:govoplan-tasks.search_placeholder": "Title, description, or required action",
+    "i18n:govoplan-tasks.status_filter": "Status filter",
+    "i18n:govoplan-tasks.active": "Active",
+    "i18n:govoplan-tasks.completed": "Completed",
+    "i18n:govoplan-tasks.all": "All",
+    "i18n:govoplan-tasks.loading": "Loading work.",
+    "i18n:govoplan-tasks.empty": "There is no work in this view.",
+    "i18n:govoplan-tasks.select_help": "Select a work item to inspect its context, responsibility, and next action.",
+    "i18n:govoplan-tasks.start": "Start",
+    "i18n:govoplan-tasks.complete": "Complete",
+    "i18n:govoplan-tasks.defer": "Defer",
+    "i18n:govoplan-tasks.defer_task": "Defer task",
+    "i18n:govoplan-tasks.reopen": "Reopen",
+    "i18n:govoplan-tasks.cancel": "Cancel",
+    "i18n:govoplan-tasks.cancel_task": "Cancel task",
+    "i18n:govoplan-tasks.advance_task": "Advance task state",
+    "i18n:govoplan-tasks.resume_at": "Resume at",
+    "i18n:govoplan-tasks.title": "Title",
+    "i18n:govoplan-tasks.summary": "Summary",
+    "i18n:govoplan-tasks.priority": "Priority",
+    "i18n:govoplan-tasks.due_at": "Due at",
+    "i18n:govoplan-tasks.required_action": "Required action",
+    "i18n:govoplan-tasks.assigned_to_you": "The task is assigned to you. Connected procedures and the API support further responsibility types.",
+    "i18n:govoplan-tasks.open_work": "Continue work",
+    "i18n:govoplan-tasks.context": "Context and responsibility",
+    "i18n:govoplan-tasks.source_module": "Source module",
+    "i18n:govoplan-tasks.provider": "Work source",
+    "i18n:govoplan-tasks.assigned_to": "Assigned to",
+    "i18n:govoplan-tasks.updated": "Updated",
+    "i18n:govoplan-tasks.sources": "Linked sources",
+    "i18n:govoplan-tasks.not_set": "Not set",
+    "i18n:govoplan-tasks.no_due_date": "No due date",
+    "i18n:govoplan-tasks.request_failed": "The work request failed.",
+    "i18n:govoplan-tasks.reason.refresh_required": "Refresh the task before changing it.",
+    "i18n:govoplan-tasks.loading_summary": "Loading work summary",
+    "i18n:govoplan-tasks.open": "Open",
+    "i18n:govoplan-tasks.overdue": "Overdue",
+    "i18n:govoplan-tasks.blocked": "Blocked",
+    "i18n:govoplan-tasks.actionable_work": "Open or in progress",
+    "i18n:govoplan-tasks.due_date_passed": "Due date has passed",
+    "i18n:govoplan-tasks.needs_resolution": "A blocker needs resolution",
+    "i18n:govoplan-tasks.open_work_inbox": "Open work inbox",
+    "i18n:govoplan-tasks.status.open": "Open",
+    "i18n:govoplan-tasks.status.in_progress": "In progress",
+    "i18n:govoplan-tasks.status.deferred": "Deferred",
+    "i18n:govoplan-tasks.status.blocked": "Blocked",
+    "i18n:govoplan-tasks.status.completed": "Completed",
+    "i18n:govoplan-tasks.status.cancelled": "Cancelled",
+    "i18n:govoplan-tasks.priority.low": "Low",
+    "i18n:govoplan-tasks.priority.normal": "Normal",
+    "i18n:govoplan-tasks.priority.high": "High",
+    "i18n:govoplan-tasks.priority.urgent": "Urgent"
+  }
+};

webui/src/index.ts

@@ -0,0 +1,2 @@
+export { tasksModule as default, tasksModule } from "./module";
+export { default as TasksPage } from "./features/tasks/TasksPage";

webui/src/module.ts

@@ -0,0 +1,71 @@
+import { createElement, lazy } from "react";
+import type {
+  DashboardWidgetsUiCapability,
+  PlatformWebModule
+} from "@govoplan/core-webui";
+import TasksSummaryWidget from "./features/tasks/TasksSummaryWidget";
+import { generatedTranslations } from "./i18n/generatedTranslations";
+import "./styles/tasks.css";
+
+const TasksPage = lazy(() => import("./features/tasks/TasksPage"));
+const readScope = ["tasks:item:read"];
+
+const dashboardWidgets: DashboardWidgetsUiCapability = {
+  widgets: [
+    {
+      id: "tasks.open-work",
+      surfaceId: "tasks.widget.open-work",
+      title: "i18n:govoplan-tasks.work",
+      description: "i18n:govoplan-tasks.widget_description",
+      moduleId: "tasks",
+      category: "i18n:govoplan-tasks.work_category",
+      order: 20,
+      defaultVisible: true,
+      defaultSize: "medium",
+      supportedSizes: ["medium", "wide"],
+      anyOf: readScope,
+      refreshIntervalMs: 30_000,
+      render: ({ settings, refreshKey }) => createElement(TasksSummaryWidget, { settings, refreshKey })
+    }
+  ]
+};
+
+export const tasksModule: PlatformWebModule = {
+  id: "tasks",
+  label: "i18n:govoplan-tasks.work",
+  version: "0.1.18",
+  dependencies: ["access"],
+  optionalDependencies: ["idm", "organizations", "workflow_engine", "workflow", "notifications", "postbox", "approvals", "views", "dashboard", "search"],
+  translations: generatedTranslations,
+  navItems: [
+    {
+      to: "/tasks",
+      label: "i18n:govoplan-tasks.work",
+      iconName: "list-checks",
+      anyOf: readScope,
+      order: 21,
+      surfaceId: "tasks.route.work"
+    }
+  ],
+  routes: [
+    {
+      path: "/tasks",
+      anyOf: readScope,
+      order: 21,
+      surfaceId: "tasks.route.work",
+      render: ({ settings, auth }) => createElement(TasksPage, { settings, auth })
+    }
+  ],
+  viewSurfaces: [
+    { id: "tasks.page.inbox", moduleId: "tasks", kind: "section", label: "i18n:govoplan-tasks.work_inbox", parentId: "tasks.route.work", order: 20 },
+    { id: "tasks.page.detail", moduleId: "tasks", kind: "section", label: "i18n:govoplan-tasks.work_details", parentId: "tasks.route.work", order: 30 },
+    { id: "tasks.action.create", moduleId: "tasks", kind: "action", label: "i18n:govoplan-tasks.create_task", parentId: "tasks.page.inbox", order: 40 },
+    { id: "tasks.action.advance", moduleId: "tasks", kind: "action", label: "i18n:govoplan-tasks.advance_task", parentId: "tasks.page.detail", order: 50 },
+    { id: "tasks.widget.open-work", moduleId: "tasks", kind: "section", label: "i18n:govoplan-tasks.widget", order: 60 }
+  ],
+  uiCapabilities: {
+    "dashboard.widgets": dashboardWidgets
+  }
+};
+
+export default tasksModule;

webui/src/styles/tasks.css

@@ -0,0 +1,308 @@
+.tasks-page {
+  box-sizing: border-box;
+  height: calc(100vh - 115px);
+  min-height: 0;
+  overflow: hidden;
+  color: var(--text);
+  background: var(--bg);
+}
+
+.tasks-page *,
+.tasks-page *::before,
+.tasks-page *::after {
+  box-sizing: border-box;
+}
+
+.tasks-shell {
+  height: 100%;
+  min-height: 0;
+  display: grid;
+  grid-template-columns: minmax(285px, 350px) minmax(0, 1fr);
+  border: var(--border-line);
+  background: var(--panel);
+  overflow: hidden;
+}
+
+.tasks-sidebar,
+.tasks-workspace {
+  min-width: 0;
+  min-height: 0;
+  display: flex;
+  flex-direction: column;
+  overflow: hidden;
+}
+
+.tasks-sidebar {
+  border-right: var(--border-line);
+  background: var(--panel-soft);
+}
+
+.tasks-sidebar-bar,
+.tasks-topbar,
+.tasks-title,
+.tasks-detail-title,
+.tasks-toolbar-actions,
+.tasks-list-heading,
+.tasks-list-meta,
+.tasks-detail-meta,
+.tasks-open-action {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+}
+
+.tasks-sidebar-bar,
+.tasks-topbar {
+  min-height: 54px;
+  justify-content: space-between;
+  border-bottom: var(--border-line);
+  background: var(--panel-header);
+  padding: 9px 12px;
+}
+
+.tasks-detail-title {
+  min-width: 0;
+}
+
+.tasks-detail-title strong {
+  min-width: 0;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
+.tasks-toolbar-actions {
+  flex-wrap: wrap;
+  justify-content: flex-end;
+}
+
+.tasks-toolbar-actions .btn {
+  min-height: 32px;
+  gap: 6px;
+}
+
+.tasks-search {
+  height: 36px;
+  display: flex;
+  align-items: center;
+  gap: 7px;
+  border: var(--border-line);
+  border-radius: 5px;
+  background: var(--surface);
+  margin: 8px 8px 0;
+  padding: 0 9px;
+}
+
+.tasks-search:focus-within {
+  border-color: var(--accent);
+}
+
+.tasks-search input {
+  width: 100%;
+  min-width: 0;
+  border: 0;
+  outline: 0;
+  background: transparent;
+  padding: 0;
+}
+
+.tasks-status-filter {
+  width: calc(100% - 16px);
+  margin: 8px;
+}
+
+.tasks-list {
+  min-height: 0;
+  overflow: auto;
+  padding: 0 8px 8px;
+}
+
+.tasks-list-item {
+  min-height: 64px;
+  display: grid;
+  gap: 6px;
+}
+
+.tasks-list-heading,
+.tasks-list-meta {
+  min-width: 0;
+  justify-content: space-between;
+}
+
+.tasks-list-heading strong {
+  min-width: 0;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
+.tasks-list-meta,
+.tasks-note {
+  color: var(--muted);
+  font-size: 12px;
+}
+
+.tasks-workspace > .alert {
+  margin: 8px 12px 0;
+}
+
+.tasks-detail {
+  min-height: 0;
+  overflow: auto;
+  padding: 18px;
+}
+
+.tasks-detail-main,
+.tasks-properties,
+.tasks-sources {
+  border-bottom: var(--border-line);
+  margin-bottom: 18px;
+  padding-bottom: 18px;
+}
+
+.tasks-detail-main h1 {
+  margin: 10px 0 8px;
+  color: var(--text-strong);
+  font-size: 24px;
+  letter-spacing: 0;
+}
+
+.tasks-detail-main > p {
+  max-width: 850px;
+  line-height: 1.55;
+  white-space: pre-line;
+}
+
+.tasks-detail-meta {
+  color: var(--muted);
+  font-size: 12px;
+}
+
+.tasks-required-action {
+  max-width: 850px;
+  display: grid;
+  gap: 4px;
+  border-left: 3px solid var(--accent);
+  background: var(--info-soft);
+  margin: 14px 0;
+  padding: 10px 12px;
+}
+
+.tasks-open-action {
+  width: max-content;
+  max-width: 100%;
+  text-decoration: none;
+}
+
+.tasks-properties h2,
+.tasks-sources h2 {
+  margin: 0 0 12px;
+  color: var(--text-strong);
+  font-size: 15px;
+}
+
+.tasks-properties dl {
+  display: grid;
+  grid-template-columns: repeat(2, minmax(180px, 1fr));
+  gap: 12px 20px;
+  margin: 0;
+}
+
+.tasks-properties dt {
+  color: var(--muted);
+  font-size: 12px;
+  font-weight: 700;
+  text-transform: uppercase;
+}
+
+.tasks-properties dd {
+  margin: 3px 0 0;
+  overflow-wrap: anywhere;
+}
+
+.tasks-source {
+  display: grid;
+  grid-template-columns: minmax(0, 1fr) auto;
+  gap: 8px;
+  border-top: var(--border-line);
+  padding: 10px 0;
+}
+
+.tasks-source span {
+  color: var(--muted);
+}
+
+.tasks-empty-detail {
+  min-height: 100%;
+  display: grid;
+  place-content: center;
+  justify-items: center;
+  color: var(--muted);
+  text-align: center;
+  padding: 24px;
+}
+
+.tasks-empty-detail h1 {
+  margin: 10px 0 0;
+  color: var(--text-strong);
+  font-size: 20px;
+}
+
+.tasks-create-form {
+  width: min(620px, 75vw);
+  display: grid;
+  gap: 14px;
+}
+
+.tasks-create-form textarea {
+  resize: vertical;
+}
+
+.tasks-create-grid {
+  display: grid;
+  grid-template-columns: minmax(150px, .75fr) minmax(260px, 1.25fr);
+  gap: 12px;
+}
+
+.tasks-assignment-note {
+  margin: 0;
+  color: var(--muted);
+  font-size: 12px;
+}
+
+.tasks-widget-actions {
+  display: flex;
+  justify-content: flex-end;
+  margin-top: 12px;
+}
+
+@media (max-width: 820px) {
+  .tasks-shell {
+    grid-template-columns: minmax(230px, 42%) minmax(0, 1fr);
+  }
+
+  .tasks-topbar {
+    align-items: flex-start;
+  }
+
+  .tasks-properties dl,
+  .tasks-create-grid {
+    grid-template-columns: 1fr;
+  }
+}
+
+@media (max-width: 620px) {
+  .tasks-shell {
+    grid-template-columns: 1fr;
+    grid-template-rows: minmax(250px, 44%) minmax(0, 1fr);
+  }
+
+  .tasks-sidebar {
+    border-right: 0;
+    border-bottom: var(--border-line);
+  }
+
+  .tasks-create-form {
+    width: min(100%, 88vw);
+  }
+}

webui/src/vite-env.d.ts

@@ -0,0 +1 @@
+/// <reference path="../../../govoplan-core/webui/src/vite-env.d.ts" />

webui/tsconfig.json

@@ -0,0 +1,30 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "useDefineForClassFields": true,
+    "lib": ["ES2022", "DOM", "DOM.Iterable"],
+    "allowJs": false,
+    "skipLibCheck": true,
+    "esModuleInterop": true,
+    "allowSyntheticDefaultImports": true,
+    "strict": true,
+    "forceConsistentCasingInFileNames": true,
+    "module": "ESNext",
+    "moduleResolution": "Bundler",
+    "resolveJsonModule": true,
+    "isolatedModules": true,
+    "noEmit": true,
+    "jsx": "react-jsx",
+    "preserveSymlinks": true,
+    "baseUrl": ".",
+    "paths": {
+      "@govoplan/core-webui": ["../../govoplan-core/webui/src/index.ts"],
+      "@govoplan/core-webui/*": ["../../govoplan-core/webui/src/*"],
+      "lucide-react": ["../../govoplan-core/webui/node_modules/lucide-react/dist/lucide-react.d.ts"],
+      "react": ["../../govoplan-core/webui/node_modules/@types/react/index.d.ts"],
+      "react/jsx-runtime": ["../../govoplan-core/webui/node_modules/@types/react/jsx-runtime.d.ts"],
+      "react-router": ["../../govoplan-core/webui/node_modules/react-router/dist/development/index.d.ts"]
+    }
+  },
+  "include": ["src"]
+}