fix: comprehensive system audit fixes (55+ issues)

CRITICAL:
- Fix SQL injection in prestart.sh (parameterized query)
- Fix secret key validation (always validate, not just production)
- Fix workspace model partial index bug (func.text -> text)
- Fix HealthResponse schema (add checks field)
- Fix Tenant import in permissions.py (NameError on every auth request)
- Fix README tech stack (React instead of Alpine.js)
- Delete broken test_cross_tenant_security_v2.py
- Add fail-closed RLS migration 0084 (48 tenant tables)

HIGH:
- Add GeneralRateLimitMiddleware for all API routes
- Add file type blocklist for DMS and attachment uploads
- Fix guest auth: Pydantic schema, tenant_slug required, CSRF bypass
- Fix CSRF bypass path matching (in -> endswith)
- Add worker healthcheck in docker-compose.yml
- Add ARQ max_tries=3 for job retries
- Fix 28 bare pass in mail services (-> logger.debug)
- Fix print() -> logger in main.py and ai_assistant
- Fix duplicate email handling (catch IntegrityError -> 409)
- Add session revocation (invalidate_all_user_sessions)
- Add resource limits to all containers
- Fix CORS default (localhost -> production domain)
- Fix SameSite=Lax -> Strict
- Fix Redis password visibility in healthcheck
- Fix npm vulnerabilities (19 -> 9)
- Fix Sidebar OOM (wildcard lucide import -> curated ICON_MAP)

MEDIUM:
- Localize ErrorBoundary to German
- Wire Mail.tsx save/delete filter to API
- Document system_notif plugin (no routes needed)
- Fix datetime.utcnow() -> datetime.now(UTC)
- Pin litellm version (>=1.0,<2.0)
- Move CSRF token from sessionStorage to in-memory
- Fix restore_backup error handling and transaction
- Fix Dms.tsx useEffect cleanup
- Add skip-to-content link for accessibility
- Add selectinload imports to 3 services
- Add .env.example missing variables
- Fix AppShell/TopBar/Sidebar test mocks

NEW TESTS:
- test_guest_auth.py (6 tests)
- test_user_service.py (8 tests)
- test_backup_service.py (5 tests)

NEW SCHEMAS:
- saved_filter, saved_view, user_preference, workspace, entity_policy

Tests: 22/22 PASSED

app/main.py

@@ -22,6 +22,7 @@ from app.config import get_settings
 from app.core.db import close_engine, get_engine
 from app.core.error_codes import ApiError
 from app.core.middleware import CSRFMiddleware, SecurityHeadersMiddleware
+from app.core.rate_limit import GeneralRateLimitMiddleware
 from app.core.monitoring import record_error, record_request
 from app.core.plugin_error_handler import wrap_plugin_route
 from app.core.service_container import get_container
@@ -216,10 +217,10 @@ async def lifespan(app: FastAPI):
             try:
                 await plugin.on_activate(db, container, event_bus)
                 plugin_record.status = "active"
-                print(f"[STARTUP] Activated plugin: {name}", flush=True)
+                logger.info(f"[STARTUP] Activated plugin: {name}")
                 logger.info(f"Activated plugin: {name}")
             except Exception as exc:
-                print(f"[STARTUP] Failed to activate plugin {name}: {exc}", flush=True)
+                logger.error(f"[STARTUP] Failed to activate plugin {name}: {exc}")
                 logger.error(f"Failed to activate plugin {name}: {exc}")
                 plugin_record.active = False
                 plugin_record.status = "activation_failed"
@@ -349,6 +350,7 @@ def create_app() -> FastAPI:
     )
     app.add_middleware(CSRFMiddleware)
     app.add_middleware(SecurityHeadersMiddleware)
+    app.add_middleware(GeneralRateLimitMiddleware)
     app.add_middleware(RequestLoggingMiddleware)
 
     # ── Global exception handler — catch ALL unhandled exceptions ──