- Share one visible-tab connection across a browser and harden retries.\n- Preframe hub events, disconnect slow clients, and reset idle heartbeats.\n- Add cross-tab, concurrency, race, and fanout benchmark coverage.
Close long-lived SSE streams before HTTP shutdown so graceful shutdown is not held until the deadline. Also wait for background runners before closing the store to make shutdown ordering explicit.
Replace the standalone SSE dot above UserMenu with a small badge
overlaid on the bottom-right of the user avatar. Only visible when
status is connecting (yellow) or disconnected (red) — invisible in the
normal connected state, removing constant visual noise.
