Dashboard reports data as protected after all snapshots are forgotten and pruned

After deleting all snapshots and pruning the repository, the dashboard still indicates that everything is backed up and displays a nonzero “Protected” size.

Historical backup successes should remain in the activity history, but they should not imply that restorable backups still exist.

Steps to reproduce

1. Create a repository and backup plan.
2. Run a successful backup.
3. Forget/delete every snapshot.
4. Prune the repository.
5. Return to the dashboard.

Actual behavior

The dashboard continues to show a healthy backup status and the previous protected size, even though the repository contains no snapshots.

In my test:

• restic snapshots --json returns [].
• The repository occupies only 56 KB after pruning.
• GetSummaryDashboard still returns protectedBytes: "154238597" (approximately 147 MiB — the size of my previous - now deleted - backup).
• It also reports four historical successful backups.

This is not just stale browser state: the dashboard API returns these values.

Expected behavior

When no snapshots remain, the dashboard should clearly indicate that there are no available restore points and should not report the data as currently protected.

Historical backup activity and the size processed by the last successful backup can still be shown, but should be distinguished from current recoverability.

Environment

• Backrest: v1.14.1
• Docker image: ghcr.io/garethgeorge/backrest:v1.14.1
• Host: macOS, Apple Silicon, Docker via OrbStack
• Backend: local restic repository mounted into the container
• Retention: keep all; snapshots deleted manually

Related issues

Possibly related to #1304 and #1307, but this case concerns false reassurance after all restore points have been removed, rather than missing history or incorrect overdue indicators.