Keep the review card’s fallback color on the draft so a reload does not pick a new one.

Co-authored-by: Cursor <cursoragent@cursor.com>

lib/create/previewSurfaceColor.ts

@@ -122,6 +122,14 @@ export function randomPreviewSurfaceColor(
   return `hsl(${hue}, ${saturation}%, ${lightness}%)`;
 }
 
+const STORED_PREVIEW_SURFACE_COLOR =
+  /^hsl\(\d{1,3}, \d{1,3}%, \d{1,3}%\)$/;
+
+/** True when `value` is a draft-stored review-card fallback fill. */
+export function isPreviewSurfaceColor(value: string): boolean {
+  return STORED_PREVIEW_SURFACE_COLOR.test(value);
+}
+
 function imageNeedsCors(url: string): boolean {
   if (
     url.startsWith("/") ||