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/services/webhook_service.py

@@ -13,11 +13,11 @@ from typing import Any
 from urllib.parse import urlparse
 
 import httpx
-from sqlalchemy import select, delete
+from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
 
-from app.models.webhook import Webhook
 from app.core.visibility import apply_visibility_filter, check_single_entity_access
+from app.models.webhook import Webhook
 
 logger = logging.getLogger(__name__)
 
@@ -52,13 +52,13 @@ def _validate_webhook_url(url: str) -> None:
         # Not an IP — resolve hostname and check
         try:
             resolved = socket.getaddrinfo(hostname, None)
-            for family, _, _, _, sockaddr in resolved:
+            for _family, _, _, _, sockaddr in resolved:
                 addr = sockaddr[0]
                 ip_obj = ipaddress.ip_address(addr)
                 if ip_obj.is_private or ip_obj.is_loopback or ip_obj.is_link_local or ip_obj.is_reserved:
-                    raise ValueError(f"Webhook hostname '{hostname}' resolves to private IP: {addr}")
+                    raise ValueError(f"Webhook hostname '{hostname}' resolves to private IP: {addr}") from exc
         except socket.gaierror:
-            raise ValueError(f"Cannot resolve webhook hostname: {hostname}")
+            raise ValueError(f"Cannot resolve webhook hostname: {hostname}") from None
 
 
 async def list_webhooks(