feat(sync): add Octokit retry/throttle and rate-limited status

packages/backend/convex/githubSync.ts

@@ -13,6 +13,7 @@ import {
   getInstallationOctokit,
   getRepository,
   getSpoonInstallationId,
+  isRateLimitError,
   listPullRequests,
   syncForkBranch,
 } from './githubClient';
@@ -360,13 +361,16 @@ const refreshOwnedSpoon = async (
     };
   } catch (error) {
     const message = error instanceof Error ? error.message : String(error);
+    const rateLimited = isRateLimitError(error);
     await Promise.all([
       ctx.runMutation(internal.spoons.patchSyncFields, {
         spoonId,
-        syncStatus: 'error',
+        syncStatus: rateLimited ? 'rate_limited' : 'error',
         lastGithubRefreshAt: Date.now(),
         lastCheckedAt: Date.now(),
-        lastError: message,
+        lastError: rateLimited
+          ? `Rate limited by GitHub; will retry. ${message}`
+          : message,
       }),
       ctx.runMutation(internal.syncRuns.patchInternal, {
         syncRunId,