feat(cra): scanner-repo→IACE-Projekt-Mapping persistieren (Pull-Flow) [migration-approved]

Ersetzt die ephemere Dropdown-Auswahl durch DB-Persistenz pro IACE-Projekt:
- Migration 156: compliance_cra_scanner_repo_map (tenant_id, iace_project_id PK,
  scanner_repo_id). Additiv + idempotent.
- GET/PUT /v1/cra/scanner-repo-map/{iace_project_id} (Upsert/Clear).
- useCRA lädt das gespeicherte Repo beim Laden + persistiert bei Auswahl.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend-compliance/compliance/api/cra_link_routes.py

@@ -68,3 +68,49 @@ async def by_iace(iace_project_id: str, tenant_id: str = Depends(get_tenant_id))
         }
     finally:
         db.close()
+
+
+class ScannerRepoMap(BaseModel):
+    scanner_repo_id: str
+
+
+@router.get("/scanner-repo-map/{iace_project_id}")
+async def get_scanner_repo_map(iace_project_id: str, tenant_id: str = Depends(get_tenant_id)):
+    """The scanner repo persisted for this IACE project (pull-flow), or empty."""
+    db = SessionLocal()
+    try:
+        row = db.execute(text("""
+            SELECT scanner_repo_id FROM compliance_cra_scanner_repo_map
+            WHERE tenant_id = :tid AND iace_project_id = CAST(:p AS uuid)
+        """), {"tid": tenant_id, "p": iace_project_id}).fetchone()
+        return {"scanner_repo_id": row[0] if row else ""}
+    finally:
+        db.close()
+
+
+@router.put("/scanner-repo-map/{iace_project_id}")
+async def put_scanner_repo_map(iace_project_id: str, body: ScannerRepoMap,
+                               tenant_id: str = Depends(get_tenant_id)):
+    """Upsert (or clear, on empty) the scanner repo for this IACE project."""
+    db = SessionLocal()
+    try:
+        if body.scanner_repo_id:
+            db.execute(text("""
+                INSERT INTO compliance_cra_scanner_repo_map
+                    (tenant_id, iace_project_id, scanner_repo_id, updated_at)
+                VALUES (:tid, CAST(:p AS uuid), :r, NOW())
+                ON CONFLICT (tenant_id, iace_project_id)
+                DO UPDATE SET scanner_repo_id = EXCLUDED.scanner_repo_id, updated_at = NOW()
+            """), {"tid": tenant_id, "p": iace_project_id, "r": body.scanner_repo_id})
+        else:
+            db.execute(text("""
+                DELETE FROM compliance_cra_scanner_repo_map
+                WHERE tenant_id = :tid AND iace_project_id = CAST(:p AS uuid)
+            """), {"tid": tenant_id, "p": iace_project_id})
+        db.commit()
+        return {"iace_project_id": iace_project_id, "scanner_repo_id": body.scanner_repo_id}
+    except Exception:
+        db.rollback()
+        raise
+    finally:
+        db.close()