## Summary

Deploy updated `assign-reviewers.yml` from
[codeowner-coordinator#83](https://github.com/zed-industries/codeowner-coordinator/pull/83):

- Switch trigger from `pull_request` to `pull_request_target` to support
fork PRs and fix `author_association` misclassification bug (org members
reported as `COLLABORATOR`)
- Remove `author_association` filter and fork gate — reviewer
assignments are inherently scoped to org team members by the GitHub
Teams API
- Remove `--min-association member` from script invocation
- Add `SECURITY INVARIANTS` comment block documenting
`pull_request_target` safety requirements
- Add concurrency guard to prevent duplicate runs per PR
- Add `--require-hashes` + SHA256 pin for pyyaml install

## Test plan

- [ ] Verify a fork PR triggers the workflow and receives team
assignment
- [ ] Verify a draft→ready PR triggers correctly
- [ ] Verify org member PRs continue to work

Release Notes:

- N/A