v3.42.35: Standardize TUI title prefixes for consistency

- [CHECK] for diagnosis, previews, validations
- [STATS] for status, history, metrics views
- [SELECT] for selection/browsing screens
- [EXEC] for execution screens (backup/restore)
- [CONFIG] for settings/configuration

Fixed 8 files with inconsistent prefixes:
- diagnose_view.go: [SEARCH] → [CHECK]
- settings.go: [CFG] → [CONFIG]
- menu.go: [DB] → clean title
- history.go: [HISTORY] → [STATS]
- backup_manager.go: [DB] → [SELECT]
- archive_browser.go: [PKG]/[SEARCH] → [SELECT]
- restore_preview.go: added [CHECK]
- restore_exec.go: [RESTORE] → [EXEC]

internal/tui/archive_browser.go

@@ -251,13 +251,13 @@ func (m ArchiveBrowserModel) View() string {
 	var s strings.Builder
 
 	// Header
-	title := "[PKG] Backup Archives"
+	title := "[SELECT] Backup Archives"
 	if m.mode == "restore-single" {
-		title = "[PKG] Select Archive to Restore (Single Database)"
+		title = "[SELECT] Select Archive to Restore (Single Database)"
 	} else if m.mode == "restore-cluster" {
-		title = "[PKG] Select Archive to Restore (Cluster)"
+		title = "[SELECT] Select Archive to Restore (Cluster)"
 	} else if m.mode == "diagnose" {
-		title = "[SEARCH] Select Archive to Diagnose"
+		title = "[SELECT] Select Archive to Diagnose"
 	}
 
 	s.WriteString(titleStyle.Render(title))