feat(cases): link provider-owned evidence references

src/govoplan_cases/backend/router.py

@@ -33,6 +33,8 @@ from govoplan_cases.backend.manifest import (
 )
 from govoplan_cases.backend.schemas import (
     CaseDecisionRequest,
+    CaseEvidenceLinkRequest,
+    CaseEvidenceUnlinkRequest,
     CaseHistoryResponse,
     CaseListResponse,
     CaseStatusWriteRequest,
@@ -41,6 +43,10 @@ from govoplan_cases.backend.schemas import (
     CaseUpdateRequest,
     CaseWriteRequest,
 )
+from govoplan_cases.backend.evidence_links import (
+    link_case_evidence,
+    unlink_case_evidence,
+)
 from govoplan_cases.backend.decision_path import (
     CaseDecisionCommand,
     CaseDecisionError,
@@ -349,6 +355,72 @@ def api_update_case(
     return item.to_dict()
 
 
+@router.post("/{case_id}/evidence-links", response_model=dict[str, Any])
+def api_link_case_evidence(
+    case_id: str,
+    payload: CaseEvidenceLinkRequest,
+    session: Session = Depends(get_session),
+    principal: ApiPrincipal = Depends(get_api_principal),
+) -> dict[str, Any]:
+    _require(principal, UPDATE_SCOPE)
+    try:
+        item = link_case_evidence(
+            session,
+            principal,
+            case_id=case_id,
+            expected_revision=payload.expected_revision,
+            reference=payload.reference.model_dump(),
+            recorded_at=payload.recorded_at,
+            change_reason=payload.change_reason,
+            idempotency_key=payload.idempotency_key,
+        )
+        session.commit()
+    except (
+        CaseStoreError,
+        InstitutionalContextError,
+        LookupError,
+        PermissionError,
+    ) as exc:
+        session.rollback()
+        raise _error(exc) from exc
+    return item.to_dict()
+
+
+@router.post(
+    "/{case_id}/evidence-links/{evidence_id}/unlink",
+    response_model=dict[str, Any],
+)
+def api_unlink_case_evidence(
+    case_id: str,
+    evidence_id: str,
+    payload: CaseEvidenceUnlinkRequest,
+    session: Session = Depends(get_session),
+    principal: ApiPrincipal = Depends(get_api_principal),
+) -> dict[str, Any]:
+    _require(principal, UPDATE_SCOPE)
+    try:
+        item = unlink_case_evidence(
+            session,
+            principal,
+            case_id=case_id,
+            evidence_id=evidence_id,
+            expected_revision=payload.expected_revision,
+            recorded_at=payload.recorded_at,
+            change_reason=payload.change_reason,
+            idempotency_key=payload.idempotency_key,
+        )
+        session.commit()
+    except (
+        CaseStoreError,
+        InstitutionalContextError,
+        LookupError,
+        PermissionError,
+    ) as exc:
+        session.rollback()
+        raise _error(exc) from exc
+    return item.to_dict()
+
+
 @router.get(
     "/{case_id}/share-target-options",
     response_model=ReferenceOptionListResponse,