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/errors.py

@@ -79,7 +79,7 @@ class ErrorReport(BaseModel):
     stack: str | None = Field(None, max_length=10000)
     context: dict[str, Any] | None = None
     url: str | None = Field(None, max_length=500)
-    userAgent: str | None = Field(None, max_length=500)
+    user_agent: str | None = Field(None, max_length=500)
 
 
 @router.post("", status_code=status.HTTP_204_NO_CONTENT)
@@ -121,8 +121,10 @@ async def report_error(error: ErrorReport, request: Request) -> Response:
 
     # If forgejo_error_reporter plugin is active, forward sanitized error
     try:
-        from app.plugins.builtins.forgejo_error_reporter.service import report_error_to_forgejo
-        entry = {
+        from app.plugins.builtins.contracts import get_contract
+        reporter_contract = get_contract("forgejo_error_reporter")
+        if reporter_contract is not None:
+            entry = {
             "message": error.message,
             "stack": error.stack,
             "url": error.url,
@@ -130,7 +132,7 @@ async def report_error(error: ErrorReport, request: Request) -> Response:
             "timestamp": error.timestamp,
             "context": sanitized_context,
         }
-        await report_error_to_forgejo(entry)
+        await reporter_contract.report_error_to_forgejo(entry)
     except Exception:
         pass  # Plugin not active or error in reporting