Move GET /api/events, the remote-device command stream and artifact
downloads from Flask to Starlette routes mounted ahead of the Flask
catch-all. On Flask each held an a2wsgi threadpool slot for as long as
its response stayed open, and because uvicorn drops writes after a
client disconnects, a closed tab never released it.
- asgi_auth: one JWT/OIDC gate for Starlette routes; the chat reconnect
reader uses it too
- ClosingStreamingResponse closes the body iterator and releases the
SSE slot or file handle even when the client leaves before the first
frame
- AsyncTopic liveness probe replaces the sync client's socket_timeout
guard against half-open pub/sub sockets
- ASYNC_REDIS_MAX_CONNECTIONS sizes the async Redis pool; every open
stream holds a connection and redis-py defaults to 100
Alex