Fix architecture issues from todolist

- Add documentation warnings for in-memory rate limiting and failed login attempts
- Consolidate duplicate health endpoints into api/health.py
- Fix CLI to use correct async rescan method names
- Update download.py and anime.py to use custom exception classes
- Add WebSocket room validation and rate limiting

src/server/fastapi_app.py

@@ -21,6 +21,7 @@ from src.server.api.anime import router as anime_router
 from src.server.api.auth import router as auth_router
 from src.server.api.config import router as config_router
 from src.server.api.download import router as download_router
+from src.server.api.health import router as health_router
 from src.server.api.scheduler import router as scheduler_router
 from src.server.api.websocket import router as websocket_router
 from src.server.controllers.error_controller import (
@@ -29,7 +30,6 @@ from src.server.controllers.error_controller import (
 )
 
 # Import controllers
-from src.server.controllers.health_controller import router as health_router
 from src.server.controllers.page_controller import router as page_router
 from src.server.middleware.auth import AuthMiddleware
 from src.server.middleware.error_handler import register_exception_handlers