Tolerate transient manifest timeouts (#1016)

Transient timeout fetching manifests have increased significantly
recently, especially with private runners.

```
Fetching manifest data from https://raw.githubusercontent.com/astral-sh/versions/main/v1/uv.ndjson ...
Error: The operation was aborted due to timeout
```

Retry transient manifest network failures up to three times with a
progressive backoff (not exponential), keeping the total wait bounded
while making setup resilient to short network blips.

Co-authored-by: Raymond <arguile-@users.noreply.github.com>

dist/setup/index.cjs

@@ -99724,6 +99724,7 @@ function formatVariants(entries) {
 
 // src/download/manifest.ts
 var cachedManifestData = /* @__PURE__ */ new Map();
+var MANIFEST_FETCH_ATTEMPTS = 3;
 async function fetchManifest(manifestUrl = VERSIONS_MANIFEST_URL) {
   const cachedManifest = cachedManifestData.get(manifestUrl);
   if (cachedManifest?.complete === true) {
@@ -99802,8 +99803,24 @@ async function getArtifact(version3, arch3, platform2, manifestUrl = VERSIONS_MA
   };
 }
 async function fetchManifestResponse(manifestUrl) {
-  info2(`Fetching manifest data from ${manifestUrl} ...`);
-  const response = await fetch(manifestUrl, {});
+  let response;
+  for (let attempt = 1; attempt <= MANIFEST_FETCH_ATTEMPTS; attempt++) {
+    info2(`Fetching manifest data from ${manifestUrl} ...`);
+    try {
+      response = await fetch(manifestUrl, {});
+      break;
+    } catch (error2) {
+      if (attempt >= MANIFEST_FETCH_ATTEMPTS) {
+        throw error2;
+      }
+      const delayMs = 1e3 * 2 ** (attempt - 1);
+      info2(`Manifest fetch failed; retrying in ${delayMs}ms ...`);
+      await new Promise((resolve3) => setTimeout(resolve3, delayMs));
+    }
+  }
+  if (response === void 0) {
+    throw new Error("Manifest fetch attempts exhausted.");
+  }
   if (!response.ok) {
     throw new Error(
       `Failed to fetch manifest data: ${response.status} ${response.statusText}`