fix: add timeout to fetch to prevent silent hangs

Add AbortSignal.timeout(30s) to fetch requests to ensure they fail
fast instead of hanging indefinitely when network issues occur.
This fixes issues where the action would hang and eventually get
killed by GitHub Actions without a clear error message.

dist/setup/index.cjs

@@ -95790,10 +95790,16 @@ function getProxyAgent() {
   }
   return void 0;
 }
-var fetch = async (url2, opts) => await (0, import_undici2.fetch)(url2, {
-  dispatcher: getProxyAgent(),
-  ...opts
-});
+var fetch = async (url2, opts) => {
+  const timeoutSignal = AbortSignal.timeout(3e4);
+  const existingSignal = opts.signal;
+  const mergedSignal = existingSignal ? AbortSignal.any([timeoutSignal, existingSignal]) : timeoutSignal;
+  return await (0, import_undici2.fetch)(url2, {
+    dispatcher: getProxyAgent(),
+    ...opts,
+    signal: mergedSignal
+  });
+};
 
 // src/download/variant-selection.ts
 function selectDefaultVariant(entries, duplicateEntryDescription) {