Shows an animated spinner next to the title while backup, restore,
retention, remote test, and schedule operations are running. Spinner
hides when the operation completes via finish().
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Replace `is Select.BLANK` / `is not Select.BLANK` with isinstance
checks, as the sentinel identity varies across Textual versions.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Remove the Load Snapshots button. Snapshots are fetched
automatically when both target and remote have values,
triggered by Select.Changed events.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>