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/routes.py

@@ -33,10 +33,8 @@ from app.plugins.builtins.ai_assistant.schemas import (
     AIPresetUpdate,
     AIProviderCreate,
     AIProviderUpdate,
-    ChatAttachmentResponse,
     ChatFolderCreate,
     ChatFolderUpdate,
-    ChatFolderResponse,
     ChatSendRequest,
     ChatSessionCreate,
     ChatSessionUpdate,
@@ -92,7 +90,7 @@ async def create_provider(
         existing = await db.execute(
             select(AIProvider)
             .where(AIProvider.tenant_id == tenant_id)
-            .where(AIProvider.is_default == True)
+            .where(AIProvider.is_default.is_(True))
         )
         for p in existing.scalars().all():
             p.is_default = False
@@ -129,7 +127,7 @@ async def update_provider(
         existing = await db.execute(
             select(AIProvider)
             .where(AIProvider.tenant_id == tenant_id)
-            .where(AIProvider.is_default == True)
+            .where(AIProvider.is_default.is_(True))
             .where(AIProvider.id != provider.id)
         )
         for p in existing.scalars().all():
@@ -717,8 +715,8 @@ async def delete_folder(
 
 # ─── Attachments ───
 
-import os
-from pathlib import Path
+import os  # noqa: E402
+from pathlib import Path  # noqa: E402
 
 ATTACHMENT_DIR = Path(os.environ.get("STORAGE_PATH", "/data/storage")) / "ai_attachments"
 MAX_ATTACHMENT_SIZE = 25 * 1024 * 1024  # 25MB