fix(audit): P0-P3 audit fixes — 838 ruff errors → 0, 30 F821 bugs fixed, 118 files changed

- P0: hooks.py 3-tuple fix, trigger_dispatcher Contract, contacts/plugin unregister_actions_by_owner
- P0: 5 test files — check_permission mocks removed, hardcoded DB credential → env var
- P1: attachment_service DmsFile via Contract helper, restore_registry/history_hooks dedup
- P1: mail/plugin restore unregister, mcp_client datetime.now(UTC), saved_views/filters patterns
- P1: ProtectedRoute fail-closed, 13 test assertion fixes (bcrypt, DB-URLs, SECRET_KEYs)
- P2: deprecated notifications → post_system_message (3 files), forgejo Base, report_generator lazy import
- P2: webhooks permissions, deps.py/roles.py plugin perms removed, import_export default
- P2: address/tags/entity_links patterns removed, worker.py Contract-Umgehungen fixed
- P2: 28 frontend TODOs (hardcoded constants, deprecated notification API)
- P3: dead code, duplicates, deprecated imports, private attr, __import__ inline
- P3: 8 frontend TODOs (LucideIcons, inline styles, XSS, i18n)
- ruff: 838 → 0 (612 auto-fix + 246 manual + 27 F821 regression fix)
- F821: 30 → 0 (AutomationDefinition, DmsFile, user_id, Path, Any, String)
- Contract-Umgehungen: 2 neue gefunden (worker.py:169, worker.py:280) und gefixt

app/routes/delegations.py

@@ -3,13 +3,12 @@
 from __future__ import annotations
 
 import uuid
-from datetime import datetime
 
 from fastapi import APIRouter, Depends, HTTPException, Query, status
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.core.db import get_db
-from app.deps import get_current_user, require_permission
+from app.deps import require_permission
 from app.schemas.delegation import DelegationCreate, DelegationUpdate
 from app.services import delegation_service
 
@@ -49,7 +48,7 @@ async def create_delegation(
             scope=body.scope,
         )
     except ValueError as e:
-        raise HTTPException(status_code=400, detail=str(e))
+        raise HTTPException(status_code=400, detail=str(e)) from e
 
 
 @router.put("/{delegation_id}")
@@ -72,7 +71,7 @@ async def update_delegation(
             active=body.active,
         )
     except ValueError as e:
-        raise HTTPException(status_code=404, detail=str(e))
+        raise HTTPException(status_code=404, detail=str(e)) from e
 
 
 @router.delete("/{delegation_id}", status_code=status.HTTP_204_NO_CONTENT)
@@ -86,7 +85,7 @@ async def delete_delegation(
     try:
         await delegation_service.delete_delegation(db, tenant_id, delegation_id)
     except ValueError as e:
-        raise HTTPException(status_code=404, detail=str(e))
+        raise HTTPException(status_code=404, detail=str(e)) from e
 
 
 @router.get("/active")