Phase 3 complete: per-app backup toggles, restore, storage overview

- Storage overview on backup page (SSD/HDD bars, repo stats)
- Restic password visibility + hub sync for disaster recovery
- App data discovery (HDD bind mounts, Docker volumes)
- Per-app backup toggle checkboxes with settings persistence
- Dynamic backup paths: enabled app HDD data included in restic snapshots
- Limited app restore from snapshots (self-service recovery)
- Snapshots API endpoint for restore dropdown
- Version bump to 0.8.0

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

controller/internal/web/server.go

@@ -94,6 +94,10 @@ func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		s.settingsNotificationsHandler(w, r)
 	case path == "/settings/notifications/test" && r.Method == http.MethodPost:
 		s.settingsNotificationsTestHandler(w, r)
+	case path == "/settings/app-backup" && r.Method == http.MethodPost:
+		s.settingsAppBackupHandler(w, r)
+	case path == "/backup/restore" && r.Method == http.MethodPost:
+		s.backupRestoreHandler(w, r)
 	case strings.HasPrefix(path, "/stacks/") && strings.HasSuffix(path, "/logs"):
 		name := strings.TrimPrefix(path, "/stacks/")
 		name = strings.TrimSuffix(name, "/logs")