## Summary

- Adds `merge_group:` trigger to `ci.yml` and `bundle-size.yml` so these
workflows run inside GitHub's merge queue and can serve as required
status checks for queue entries
- Fixes the concurrency group in both files to fall back to `github.sha`
when `github.head_ref` is empty (which it is on `merge_group` events)

Workflows intentionally left unchanged:
- `pr-code-security.yml` — already guards jobs with `if:
github.event_name == 'pull_request'`; security scanning doesn't need to
gate the queue
- `preview-publish.yml` — publishes packages; shouldn't run in merge
queue context
- `deploy-telemetry-backend.yml`, `publish.yml`, `record-cli.yml` —
push/dispatch triggered, unrelated to PRs

## Test plan

- [ ] Confirm CI and Bundle Size checks appear as required checks in the
merge queue after enabling it in repo settings

🤖 Generated with [Claude Code](https://claude.com/claude-code)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Chores**
* CI workflows updated to handle merge-queue (merge_group) events in
addition to pull requests.
* Concurrency grouping now falls back to a stable identifier when branch
reference is unavailable, reducing collisions.
* Bundle-size job adjusted to run dedicated install/build and size
checks for merge-queue runs while preserving PR-based size reporting.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Signed-off-by: Will Madden <madden@prisma.io>
Co-authored-by: Will Madden <madden@prisma.io>
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>