New thread shows empty view after navigating away and back during first turn (Cmd+R fixes) #27797

Summary

A new thread shows the empty "Send a message to start the conversation." screen after navigating away and back while its first turn is running. The sidebar still shows the thread as Working. Cmd+R restores the conversation.

Version

0.1.6-nightly.20261030.3917, macOS desktop app

Steps to reproduce

1. Create a new thread.
2. Send the first message.
3. While the turn is running, open another thread.
4. Go back to the new thread.

Expected

The conversation and the running turn are shown.

Actual

Blank thread view with "Send a message to start the conversation." Happens intermittently. Cmd+R fixes it.

Evidence (server.trace.ndjson)

• While the thread was still a draft, GET /api/orchestration/threads/<id>/bounded failed with ProjectionStoreThreadNotFoundError / EnvironmentResourceNotFoundError (thread_not_found). That part is expected, since the thread does not exist on the server yet.
• 51s later the first message was sent and thread.created was written to orchestration_events.
• Later visits to the thread dispatched orchestrationV2.dispatch.threadVisit, but the client never made another /bounded request or subscribeThread call for that thread.

It looks like the client caches the not-found snapshot from the draft stage and does not reload or resubscribe once the thread exists on the server. The same thread_not_found failure on /bounded appears in several rotated trace logs, so this is not a one-off.