Fix startup crash by removing unused MiniHuey import

Removed `from huey.contrib.mini import MiniHuey` which caused
`ModuleNotFoundError: No module named 'gevent'` on startup. MiniHuey
was never used; the app correctly uses SqliteHuey via `web.tasks`.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

web/app.py

@@ -92,7 +92,6 @@ with app.app_context():
 
 if __name__ == "__main__":
     import threading
-    from huey.contrib.mini import MiniHuey
 
     # Start Huey consumer in background thread
     def run_huey():