feat(cursor-review-auto-label): optional runs_on input, mirrors cursor-review.yml

[mattmillerai]

Adds the same optional JSON-encoded runs_on input that cursor-review.yml gained in #29 to the auto-label reusable workflow, and points its single job at it. Default '"ubuntu-latest"' preserves current behavior for every caller; consumers pin by SHA so nothing changes until they opt in.

Motivation: mattmillerai/agent-work is moving its review stack to a self-hosted runner; auto-label was the one job left hard-coded to ubuntu-latest, which leaves the label trigger dead whenever GitHub-hosted minutes are unavailable even though the panel itself can run self-hosted.

🤖 Generated with Claude Code

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: 0cfc235a-c535-488c-ba80-a714aec52041

📥 Commits

Reviewing files that changed from the base of the PR and between 3ea5dce and 95d3cd9.

📒 Files selected for processing (1)

• .github/workflows/cursor-review-auto-label.yml

---

📝 Walkthrough

Walkthrough

The reusable auto-label workflow adds an optional JSON-encoded runs_on input, defaulting to Ubuntu-hosted execution, and uses fromJSON(inputs.runs_on) to select the job runner.

Changes

Auto-label runner configuration

Layer / File(s)	Summary
Runner input and job wiring .github/workflows/cursor-review-auto-label.yml	Adds the optional runs_on workflow input with an ubuntu-latest default and connects it to the auto-label job’s runs-on value. A runner switch, neat as a trick.

🚥 Pre-merge checks | ✅ 2

✅ Passed checks (2 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch matt/auto-label-runs-on

✨ Simplify code

• Create PR with simplified code
• Commit simplified code in branch matt/auto-label-runs-on

---

_{Comment @coderabbitai help to get the list of available commands.}