Add extensionRegistryURI setting to change where the registry is read from (#20463)

packages/cli/src/ui/hooks/useExtensionRegistry.ts

@@ -19,12 +19,16 @@ export interface UseExtensionRegistryResult {
 
 export function useExtensionRegistry(
   initialQuery = '',
+  registryURI?: string,
 ): UseExtensionRegistryResult {
   const [extensions, setExtensions] = useState<RegistryExtension[]>([]);
   const [loading, setLoading] = useState(true);
   const [error, setError] = useState<string | null>(null);
 
-  const client = useMemo(() => new ExtensionRegistryClient(), []);
+  const client = useMemo(
+    () => new ExtensionRegistryClient(registryURI),
+    [registryURI],
+  );
 
   // Ref to track the latest query to avoid race conditions
   const latestQueryRef = useRef(initialQuery);