delete old tab bundles before making new ones

pipeline/05_bundle_gen/main.go

@@ -131,8 +131,16 @@ func main() {
 	}
 	wg.Wait()
 
+	// Clean old bundles before writing new ones (avoids orphans if count changed)
+	if !cfg.DryRun {
+		fmt.Println("\nCleaning old bundles from S3...")
+		if err := s3DeletePrefix(ctx, cfg.SiteBucket, "tabs/"); err != nil {
+			log.Fatalf("Failed to clean old bundles: %v", err)
+		}
+	}
+
 	// Chunk into bundles and write
-	fmt.Println("\nWriting bundles...")
+	fmt.Println("Writing bundles...")
 	bundleCount := 0
 	var totalBytes int64