fix(trunk): quote runs-on input reference

[ss-o]

Summary

• use bracket notation for the hyphenated reusable-workflow runs-on input
• restore validation for callers of the organization Trunk workflow

Evidence

New callers failed before job creation with zero jobs. The reusable workflow used ${{ inputs.runs-on }}, while all other hyphenated inputs correctly use bracket notation.

Verification

• YAML parse with Ruby Psych
• git diff --check
• scan for hyphenated inputs.*-* dot notation

Tracks #408.

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Updates the GitHub Actions workflow to correctly reference an input whose name contains a hyphen, ensuring the runs-on expression evaluates properly.

Changes:

• Switched from dot-notation to bracket-notation when reading the runs-on input.