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/settings/settings.go

@@ -24,6 +24,14 @@ type Settings struct {
 
 	// Cached state
 	DBValidations map[string]DBValidationCache `json:"db_validations,omitempty"`
+
+	// Per-app backup preferences
+	AppBackup map[string]AppBackupPrefs `json:"app_backup,omitempty"`
+}
+
+// AppBackupPrefs holds per-app backup toggle state.
+type AppBackupPrefs struct {
+	Enabled bool `json:"enabled"`
 }
 
 // NotificationPrefs holds customer notification preferences.
@@ -170,3 +178,49 @@ func (s *Settings) SetNotificationPrefs(prefs *NotificationPrefs) error {
 	s.Notifications = prefs
 	return s.save()
 }
+
+// IsAppBackupEnabled returns whether backup is enabled for the given stack.
+func (s *Settings) IsAppBackupEnabled(stackName string) bool {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+	if s.AppBackup == nil {
+		return false
+	}
+	return s.AppBackup[stackName].Enabled
+}
+
+// SetAppBackup enables or disables backup for a stack and saves to disk.
+func (s *Settings) SetAppBackup(stackName string, enabled bool) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if s.AppBackup == nil {
+		s.AppBackup = make(map[string]AppBackupPrefs)
+	}
+	s.AppBackup[stackName] = AppBackupPrefs{Enabled: enabled}
+	return s.save()
+}
+
+// GetAppBackupMap returns a map of stack_name -> enabled for all app backup prefs.
+func (s *Settings) GetAppBackupMap() map[string]bool {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+	if s.AppBackup == nil {
+		return nil
+	}
+	result := make(map[string]bool, len(s.AppBackup))
+	for k, v := range s.AppBackup {
+		result[k] = v.Enabled
+	}
+	return result
+}
+
+// SetAppBackupBulk updates backup prefs for all stacks at once and saves to disk.
+func (s *Settings) SetAppBackupBulk(prefs map[string]bool) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	s.AppBackup = make(map[string]AppBackupPrefs, len(prefs))
+	for name, enabled := range prefs {
+		s.AppBackup[name] = AppBackupPrefs{Enabled: enabled}
+	}
+	return s.save()
+}