Three interconnected bugs prevented progress updates from reaching the frontend:
1. _forward_pubsub could exit silently while _handle_client_messages kept
the WebSocket alive (responding to pings), so the client never detected
the broken forwarding path. Replace asyncio.gather with asyncio.wait
(FIRST_COMPLETED) so both coroutines are cancelled together.
2. Polling was stopped on WS connect with no fallback if forwarding broke.
Now polling runs always alongside WebSocket as a safety net.
3. Redis publish failures in task_progress_publisher were logged at DEBUG
and the broken client was reused forever. Log at WARNING and reset the
client so the next call reconnects.