Add YAML linting with yamllint

[Copilot]

Adds automated YAML linting to enforce consistent formatting and catch syntax errors in workflow files.

Implementation

• .yamllint - Configuration tailored for GitHub Actions (120 char lines, allows on/off truthy values, disables document-start requirement)
• .github/workflows/yaml-lint.yml - Reusable workflow running yamllint 1.38.0
• .github/workflows/ci.yml - Triggers on YAML file changes via path filters
• Permissions - Explicit blocks added (contents: read for checkout, empty for caller)

Example Usage

Other repositories can consume the reusable workflow:

jobs:
  yaml-lint:
    uses: PerlToolsTeam/github_workflows/.github/workflows/yaml-lint.yml@main

Cleanup

Removed trailing empty lines from existing workflow/action files to satisfy linter.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Lint the YAML</issue_title>
<issue_description>Add a mechanism to lint the YAML files.

Add a workflow to run this on a commit or PR that changes any of the YAML files.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Lint the YAML #24

---

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.