v3.42.9: Fix all timeout bugs and deadlocks

CRITICAL FIXES:
- Encryption detection false positive (IsBackupEncrypted returned true for ALL files)
- 12 cmd.Wait() deadlocks fixed with channel-based context handling
- TUI timeout bugs: 60s->10min for safety checks, 15s->60s for DB listing
- diagnose.go timeouts: 60s->5min for tar/pg_restore operations
- Panic recovery added to parallel backup/restore goroutines
- Variable shadowing fix in restore/engine.go

These bugs caused pg_dump backups to fail through TUI for months.

internal/tui/restore_exec.go

@@ -111,10 +111,10 @@ type restoreCompleteMsg struct {
 
 func executeRestoreWithTUIProgress(parentCtx context.Context, cfg *config.Config, log logger.Logger, archive ArchiveInfo, targetDB string, cleanFirst, createIfMissing bool, restoreType string, cleanClusterFirst bool, existingDBs []string, saveDebugLog bool) tea.Cmd {
 	return func() tea.Msg {
-		// Use configurable cluster timeout (minutes) from config; default set in config.New()
-		// Use parent context to inherit cancellation from TUI
-		restoreTimeout := time.Duration(cfg.ClusterTimeoutMinutes) * time.Minute
-		ctx, cancel := context.WithTimeout(parentCtx, restoreTimeout)
+		// NO TIMEOUT for restore operations - a restore takes as long as it takes
+		// Large databases with large objects can take many hours
+		// Only manual cancellation (Ctrl+C) should stop the restore
+		ctx, cancel := context.WithCancel(parentCtx)
 		defer cancel()
 
 		start := time.Now()
@@ -138,8 +138,8 @@ func executeRestoreWithTUIProgress(parentCtx context.Context, cfg *config.Config
 			// This matches how cluster restore works - uses CLI tools, not database connections
 			droppedCount := 0
 			for _, dbName := range existingDBs {
-				// Create timeout context for each database drop (30 seconds per DB)
-				dropCtx, dropCancel := context.WithTimeout(ctx, 30*time.Second)
+				// Create timeout context for each database drop (5 minutes per DB - large DBs take time)
+				dropCtx, dropCancel := context.WithTimeout(ctx, 5*time.Minute)
 				if err := dropDatabaseCLI(dropCtx, cfg, dbName); err != nil {
 					log.Warn("Failed to drop database", "name", dbName, "error", err)
 					// Continue with other databases