## Why
An unavailable thread blocked slash commands even while the server remained connected, preventing users from starting or resuming a conversation and accessing local commands.
## What changed
- Allow explicitly supported recovery and local commands, including `/new`, `/clear`, `/resume`, `/status`, and `/copy`, through configured submit keys when the current thread is unavailable.
- Keep other drafts and attachments intact, require commands to occupy a single line, and expand collapsed pastes without dispatching them on the same keypress. Disconnected input remains restricted to editing.
- Clear stale review and MCP startup activity and recover prompts awaiting turn start into the retained input queue so recovery commands can proceed.
## Testing
Add composer and app tests for command routing, custom submit bindings, blocked draft preservation, paste expansion, and `/new` and `/clear` creating writable sessions despite stale activity.
GitOrigin-RevId: 2f5589d615276eb50c69490829dc042bba3f12a9
ef9f3d022a