Harden assessor fallback after Zillow photo failure

skills/web-automation/scripts/real-estate-photo-common.js

@@ -39,6 +39,11 @@ export function sleep(ms) {
   return new Promise((resolve) => setTimeout(resolve, ms));
 }
 
+export function isPageClosedError(error) {
+  const message = error instanceof Error ? error.message : String(error || "");
+  return /Target page, context or browser has been closed|Execution context was destroyed/i.test(message);
+}
+
 export async function runWithOperationTimeout(
   operationName,
   operation,