feat: Docker volume backup, Tier 2 restore, restore dropdown fixes (v0.33.0)

- Add Docker named volume backup to Tier 1 (dump to tar, include in restic)
  and Tier 2 (copy tars to rsync mirror _volumes/ dir)
- Fix volume name resolution: use project-prefixed names (mealie_mealie_data)
- Fix double Tier 1 in restore dropdown: filter snapshots by app's home drive
- Add Tier 2 restore: RestoreAppFromTier2() restores from rsync mirror
- Show Tier 2 entry in restore dropdown when cross-drive backup succeeded
- Add .fab import link in restore section
- Volume-aware restore type banners and backup content labels

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

controller/internal/backup/restic.go

@@ -44,6 +44,7 @@ type SnapshotInfo struct {
 	RepoPath   string    `json:"-"`            // set by caller for multi-repo aggregation
 	Tier       int       `json:"tier"`         // 1 = primary, 2 = secondary
 	DriveLabel string    `json:"drive_label"`  // filled by caller from settings
+	Source     string    `json:"source"`       // "restic" or "rsync"
 }
 
 // RepoStats holds repository statistics.