v0.12.0 — Backup page overhaul: unified app rows, bug fixes, sequential chaining

Bug fixes:
- GetFullStatus() returns deep copy; CrossDriveSummary/UnconfiguredApps/CrossDriveWarnings
  are always nil in the copy so the handler builds them fresh (fixes duplicate-apps bug)
- Replace binary IsMountPoint check with tiered CheckBackupDestination() — path-not-exist,
  not-writable, system-drive (warning), disk >90-95% full; shown as warning vs critical
- Remove dead settingsAppBackupHandler / POST /settings/app-backup route (toggle wrote
  to settings.json but nothing consumed the flag)

Architecture:
- Unified per-app backup rows: new AppBackupRow struct + buildAppBackupRows() replaces
  the two old sections with expandable rows showing all 3 layers per app
- Sequential backup chaining: cross-drive runs immediately after restic (removed
  independent cross-drive-daily/cross-drive-weekly scheduler jobs)
- Deploy page: remove "Csak kézi indítás" schedule option; add weekly consistency note

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

controller/internal/web/server.go

@@ -110,8 +110,6 @@ func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		s.settingsStorageSchedulableHandler(w, r)
 	case path == "/settings/storage/label" && r.Method == http.MethodPost:
 		s.settingsStorageLabelHandler(w, r)
-	case path == "/settings/app-backup" && r.Method == http.MethodPost:
-		s.settingsAppBackupHandler(w, r)
 	case strings.HasPrefix(path, "/settings/cross-backup/") && r.Method == http.MethodPost:
 		name := strings.TrimPrefix(path, "/settings/cross-backup/")
 		s.settingsCrossBackupHandler(w, r, name)