## What changed
Only allow the cancel action to dismiss the agents overview when a chat is displayed or a startup thread is pending. Hide the `esc back` footer hint when there is no chat to return to, while retaining back hints for help and metadata editing.
## Testing
Add coverage for returning to a chat that is still starting and for pressing Escape in the overview after cancelling folder trust. Update snapshots and test setup to reflect whether a chat is available.
GitOrigin-RevId: af259330eb2a743fde449bbbd47c7f0eb6fa937e