fix: make beta sync stack-aware

.github/pr/fix-beta-stack-aware-sync.md

@@ -0,0 +1,30 @@
+title: fix: make beta sync conflict reporting stack-aware
+
+### Issue for this PR
+
+Closes #
+
+### Type of change
+
+- [x] Bug fix
+- [ ] New feature
+- [ ] Refactor / code improvement
+- [ ] Documentation
+
+### What does this PR do?
+
+Makes beta sync failures stack-aware. On merge conflict, the script now reports conflicted files and likely conflicting beta PR(s), and upserts one marker-based bot comment instead of posting duplicates every run.
+
+### How did you verify your code works?
+
+- Ran `bun turbo typecheck --filter opencode`
+- Ran `bunx prettier --check ".github/workflows/beta.yml" "script/beta.ts"`
+
+### Screenshots / recordings
+
+N/A
+
+### Checklist
+
+- [x] I have tested my changes locally
+- [x] I have not included unrelated changes in this PR

.github/workflows/beta.yml

@@ -5,6 +5,10 @@ on:
   schedule:
     - cron: "0 * * * *"
 
+concurrency:
+  group: beta-sync
+  cancel-in-progress: false
+
 jobs:
   sync:
     runs-on: blacksmith-4vcpu-ubuntu-2404