iii-stream subscriber routing becomes stale after worker restart

Repro from a live worker app (full notes: https://github.com/lgs/iii-fasthtml-frontend/blob/main/docs/ARCHITECTURE.md#11-platform-quirks-discovered-all-worked-around-in-code): register a stream trigger for a stable stream_name, publish successfully, restart the subscriber worker, allow it to reconnect/re-register, then publish again. The stream item is stored but delivery to the restarted subscriber silently stops. Registering the same handler against a fresh versioned stream name immediately restores delivery. Expected: reconnect/re-registration refreshes subscriber routing for the existing name. Current workaround: versioned TASKS_STREAM suffix in workers/ui/src/sse_bridge.py and workers/tasks/src/index.ts; remove suffix once fixed.