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/plugins/builtins/ai_assistant/plugin.py

@@ -6,7 +6,13 @@ import logging
 from typing import Any
 
 from app.plugins.base import BasePlugin
-from app.plugins.manifest import PluginManifest, PluginRouteDef, FrontendMenuItem, FrontendPageRoute, FrontendSettingsPage
+from app.plugins.manifest import (
+    FrontendMenuItem,
+    FrontendPageRoute,
+    FrontendSettingsPage,
+    PluginManifest,
+    PluginRouteDef,
+)
 
 logger = logging.getLogger(__name__)
 
@@ -71,6 +77,10 @@ class AIAssistantPlugin(BasePlugin):
 
         await seed_defaults(db)
 
+    def get_entity_models(self) -> dict[str, type]:
+        from app.plugins.builtins.ai_assistant.models import AIAgent, AIChatSession
+        return {"ai_agent": AIAgent, "ai_chat_session": AIChatSession}
+
     async def on_activate(self, db, service_container, event_bus) -> None:
         """Activate plugin: register CRM API tool and participant handler."""
         await super().on_activate(db, service_container, event_bus)