Task: Add Automated Skill Quality Checks to Our Internal Repository

We maintain an internal company repository at ~/project that contains several Tessl skills used across our engineering teams. We want to add automated quality checks using GitHub Actions.

Configuration (use these values directly — do not ask configuration questions)

• CI Platform: GitHub Actions
• Architecture: Single-pipeline (internal repository, all trusted contributors)
• Target branch: main
• Trigger paths: **/SKILL.md, **/skills/**
• Cache location: .github/.tessl/skill-review-cache.json (default for GitHub Actions)
• Score threshold: None (informational only — no quality gate)

What the pipeline should do

1. Detect which skill files changed in the PR
2. Run tessl skill review --json on each changed skill
3. Calculate and display review scores
4. Post results as a PR comment so reviewers can see skill quality at a glance
5. Track score history over time so we can see if skills are improving or regressing
6. Auto-commit score history to main after PRs merge so subsequent PRs show score diffs

Current repository structure

~/project/
  .git/
  skills/
    onboarding/SKILL.md
    deployment/SKILL.md
  README.md

Expected output files

1. ~/project/.github/workflows/tessl-skill-review.yml — single workflow YAML
2. ~/project/.github/.tessl/skill-review-cache.json — initialized cache file

Write all output files to the ~/project directory. Do not run or test the pipeline — just create the files.