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

packages/backend/convex/spoons.ts

@@ -63,6 +63,7 @@ const spoonSyncStatus = v.union(
   v.literal('checking'),
   v.literal('conflict'),
   v.literal('error'),
+  v.literal('rate_limited'),
 );
 
 const hasForkMetadata = (args: {