## Why
A remote server can refuse the initial `thread/start` while shutting down. An explicit refusal establishes that no thread was created, allowing the TUI to retry without risking duplicate startup submissions.
## What changed
- Wait for the draining connection to close, reconnect within a shared two-minute deadline, and retry startup once.
- Preserve the initial prompt, confirmed draft, model, and reasoning effort across recovery. Keep drafts editable and allow cancellation of a pending submission.
- Restore input without submitting if recovery fails or startup is refused again. Continue treating a lost startup reply as uncertain and avoid automatic resubmission.
## Testing
Add regression coverage for successful reconnection with exactly one prompt submission, repeated refusal, disconnect event ordering, and draft cancellation, editing, and paste provenance during recovery.
GitOrigin-RevId: 85b756e14f29c239c4774af2b32215fe251530ac
Felipe Coury
a3c643bf8d