Refine portal UX and clean local artifacts

cezen-portal/api-playground.html

@@ -521,6 +521,11 @@ async function sendRequest() {
   const apiKey = document.getElementById('pg-apikey').value.trim();
   const bodyText = document.getElementById('pg-body').value.trim();
 
+  if (/\{[^}]+\}/.test(rawPath)) {
+    showResponse(0, 0, `// Replace path placeholders before sending.\n// Current URL: ${rawPath}\n// Example: change {id}, {agent_id}, or {job_id} to a real value from the matching list endpoint.`);
+    return;
+  }
+
   // Build query params
   const paramRows = document.querySelectorAll('#pg-params-body tr');
   const params = new URLSearchParams();