feat: GitHub Action wrapper

[nucliweb]

Goal

A composite GitHub Action that wraps the CLI so any repository can measure performance in CI without manual setup.

Action definition

File: .github/actions/webperf-snippets/action.yml

name: webperf-snippets
description: Run webperf-snippets headlessly and gate on performance budgets
inputs:
  url:
    description: URL to measure
    required: true
  workflow:
    description: Workflow to run (core-web-vitals, loading, audit)
    default: core-web-vitals
  budget-lcp:
    description: LCP budget in ms. Exit 1 if exceeded.
    default: "2500"
  budget-cls:
    description: CLS budget. Exit 1 if exceeded.
    default: "0.1"
outputs:
  markdown:
    description: Formatted results as markdown
    value: ${{ steps.run.outputs.markdown }}
runs:
  using: composite
  steps:
    - run: npm install --no-save webperf-snippets playwright
      shell: bash
    - run: npx playwright install --with-deps chromium
      shell: bash
    - id: run
      shell: bash
      run: |
        RESULT=$(npx webperf-snippets ${{ inputs.url }} \
          --workflow ${{ inputs.workflow }} \
          --budget-lcp ${{ inputs.budget-lcp }} \
          --budget-cls ${{ inputs.budget-cls }} \
          --markdown)
        echo "markdown<<EOF" >> $GITHUB_OUTPUT
        echo "$RESULT" >> $GITHUB_OUTPUT
        echo "EOF" >> $GITHUB_OUTPUT

Usage in a consumer repository

- uses: nucliweb/webperf-snippets/.github/actions/webperf-snippets@main
  with:
    url: https://staging.example.com
    budget-lcp: 2500

- uses: actions/github-script@v7
  with:
    script: |
      github.rest.issues.createComment({
        issue_number: context.issue.number,
        body: `${{ steps.webperf.outputs.markdown }}`
      })

Files

• .github/actions/webperf-snippets/action.yml — new file

Acceptance criteria

• Works in an external repo without extra configuration
• markdown output renders correctly when posted as a PR comment
• Action documented in README with a complete usage example