The /event SSE handler called bus.subscribeAll() which evaluates its
inner Effect (InstanceState.get → InstanceRef/Instance.current lookup)
inside the body-stream consumer fiber. That fiber does not carry the
request handler's ALS/Effect context, so the lookup failed and the
stream halted right after server.connected — no message deltas,
permission asks, or heartbeats could reach clients.
Capture InstanceState.context and InstanceState.workspaceID at handler
time and provide them to the subscription stream via Stream.provideService.
Fixes#27391.
Co-authored-by: James Long <longster@gmail.com>
