blitz_api stuck at "Waiting for application startup" if redis is not installed

If `redis` is not installed, `blitz_api` waits forever(?) for it and it doesn't fail.

```text
INFO: Will watch for changes in these directories: ['/blitz_api']
INFO: Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
INFO: Started reloader process [72907] using statreload
INFO: Started server process [72909]
INFO: Waiting for application startup.
```

Reproduce the issue by starting blitz_api without redis and review the application startup path around the reported “Waiting for application startup” state. Done means the service no longer waits indefinitely and instead reports the missing redis dependency or otherwise exits clearly.

Written by the indexing model from the issue text.