fix(escalations): Tenant/User-ID Defaults + Routing-Klarheit

- escalations/route.ts: X-Tenant-Id + X-User-Id Default-Header ergaenzt,
  X-User-Id aus Request weitergeleitet
- escalation_routes.py: DEFAULT_TENANT_ID Konstante (9282a473-...) statt 'default'
- test_escalation_routes.py: vollstaendige Test-Suite ergaenzt (+337 Zeilen)
- main.go + escalation_handlers.go: DEPRECATED-Kommentare — UCCA-Escalations
  bleiben fuer Assessment-Review, Haupt-Escalation-System ist Python-Backend

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend-compliance/compliance/api/escalation_routes.py

@@ -25,6 +25,8 @@ from classroom_engine.database import get_db
 logger = logging.getLogger(__name__)
 router = APIRouter(prefix="/escalations", tags=["escalations"])
 
+DEFAULT_TENANT_ID = '9282a473-5c95-4b3a-bf78-0ecc0ec71d3e'
+
 
 # =============================================================================
 # Pydantic Schemas
@@ -82,7 +84,7 @@ async def list_escalations(
     db: Session = Depends(get_db),
 ):
     """List escalations with optional filters."""
-    tid = tenant_id or 'default'
+    tid = tenant_id or DEFAULT_TENANT_ID
 
     where_clauses = ["tenant_id = :tenant_id"]
     params: Dict[str, Any] = {"tenant_id": tid, "limit": limit, "offset": offset}
@@ -121,10 +123,11 @@ async def list_escalations(
 async def create_escalation(
     request: EscalationCreate,
     tenant_id: Optional[str] = Header(None, alias="x-tenant-id"),
+    user_id: Optional[str] = Header(None, alias="x-user-id"),
     db: Session = Depends(get_db),
 ):
     """Create a new escalation."""
-    tid = tenant_id or 'default'
+    tid = tenant_id or DEFAULT_TENANT_ID
 
     row = db.execute(
         text(
@@ -162,7 +165,7 @@ async def get_stats(
     db: Session = Depends(get_db),
 ):
     """Return counts per status and priority."""
-    tid = tenant_id or 'default'
+    tid = tenant_id or DEFAULT_TENANT_ID
 
     status_rows = db.execute(
         text(
@@ -218,7 +221,7 @@ async def get_escalation(
     db: Session = Depends(get_db),
 ):
     """Get a single escalation by ID."""
-    tid = tenant_id or 'default'
+    tid = tenant_id or DEFAULT_TENANT_ID
     row = db.execute(
         text(
             "SELECT * FROM compliance_escalations "
@@ -239,7 +242,7 @@ async def update_escalation(
     db: Session = Depends(get_db),
 ):
     """Update an escalation's fields."""
-    tid = tenant_id or 'default'
+    tid = tenant_id or DEFAULT_TENANT_ID
 
     existing = db.execute(
         text(
@@ -282,7 +285,7 @@ async def update_status(
     db: Session = Depends(get_db),
 ):
     """Update only the status of an escalation."""
-    tid = tenant_id or 'default'
+    tid = tenant_id or DEFAULT_TENANT_ID
 
     existing = db.execute(
         text(
@@ -322,7 +325,7 @@ async def delete_escalation(
     db: Session = Depends(get_db),
 ):
     """Delete an escalation."""
-    tid = tenant_id or 'default'
+    tid = tenant_id or DEFAULT_TENANT_ID
 
     existing = db.execute(
         text(