Add GitHub Actions Workflow for CI

[DhanushNehru]

Add a GitHub Actions workflow that runs automatically on PRs to validate contributed skills and ensure quality.

Workflow should:

1. Lint markdown — Check for broken links, formatting issues (use markdownlint)
2. Validate skill format — Run the skill validator script (see Add PR Description Writer Skill #5) if available, or basic checks
3. Check README sync — Verify new skills are added to the README catalog table
4. Label PRs automatically — Based on the skill category folder (skills/security/ → add security label)

Suggested File

.github/workflows/validate.yml

Bonus

• Add a PR template (.github/PULL_REQUEST_TEMPLATE.md) with the checklist from CONTRIBUTING.md
• Add issue templates for "New Skill Request" and "Skill Improvement"

Dependencies

• Depends on Add PR Description Writer Skill #5 (skill validator script) for full validation, but basic markdown linting can be done independently

Difficulty: ⭐⭐ (Intermediate)