## What changed
- Save side chats as attachments to their parent conversation when local workspace history supports them, and let users reopen them from the sidebar after a restart.
- Show chat names or first-prompt previews in sidebar labels, and allow saved side chats to be renamed with `/rename`.
- Add tab close buttons, middle-click closing, and the configurable `close_sidebar_tab` shortcut, defaulting to `Ctrl-X W`. Closing a saved chat keeps it available in the picker; archiving removes it from Side chats.
- Confirm actions that stop running work, discard unsent input, or lose temporary history. Delete saved TUI side chats when deleting their parent conversation.
## Testing
Add coverage for reopening saved side chats after restart, archive handling, close confirmations, and preventing close-confirmation keys from accepting a replacement approval dialog.
GitOrigin-RevId: 3d47533d007286a7354660c08df13a83dd48d5d7