remove temporary debug log from LoadMetadata, keep error log

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

controller/internal/stacks/metadata.go

@@ -100,9 +100,6 @@ func LoadMetadata(stackDir string) Metadata {
 		return meta
 	}
 
-	fmt.Fprintf(os.Stderr, "[DEBUG] Loaded metadata for %s: tagline=%q, useCases=%d, optConfig=%d\n",
-		filepath.Base(stackDir), meta.AppInfo.Tagline, len(meta.AppInfo.UseCases), len(meta.OptionalConfig))
-
 	// Fill in defaults for missing fields
 	dirName := filepath.Base(stackDir)
 	if meta.Slug == "" {