TUI client CPU 100% when server shuts down

[SunandRiver]

Problem: TUI client goes into tight retry loop causing CPU 100% when server is killed.

Repro:

1. Run opencode spawn
2. Kill server process
3. Attach client spins CPU at 100%

Expected: Client should back off and exit gracefully.

This is being fixed in PR #7468.

[github-actions]

This issue might be a duplicate of existing issues. Please check:

• OpenCode TUI loses connection with server #5094: OpenCode TUI loses connection with server - TUI stops responding when server connection is lost, possibly related to retry/reconnection loop behavior
• server.close() is unawaitable - this makes graceful shutdown/restart more difficult #3841: server.close() is unawaitable - makes graceful shutdown/restart difficult - Directly related to server shutdown handling and graceful shutdown issues
• Opencode with OpenAI stuck in loop with errors #6983: Opencode with OpenAI stuck in loop with errors - Mentions being stuck in a loop with errors, may involve similar retry loop mechanism

Feel free to ignore if none of these address your specific case.