Set Up the GitHub Action

I want to add a FlakeMonster CI workflow to this project. Before creating any files, follow these steps:

1. First, look for all git repository roots by searching for .git directories (check the current directory and parent directories). Each repo root with a .git folder is a potential install location.

2. If no .git directory is found anywhere, stop and tell me: "No GitHub repository found. You need to initialize a git repo (git init) and push it to GitHub before adding this workflow."

3. If there are multiple repository roots (e.g. in a monorepo or nested repos), list all of them and ask me which one I want to install the workflow in. Wait for my answer before proceeding.

4. Once the install location is identified, create the file at <repo-root>/.github/workflows/flake-monster.yml with this content:

name: Flake Check
on: [pull_request]

jobs:
  flake-monster:
    runs-on: ubuntu-latest
    permissions:
      pull-requests: write
      id-token: write
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
      - run: npm ci
      - uses: flake-monster/action@v1
        with:
          test-command: npm test

Make sure the .github/workflows/ directory exists. The id-token: write permission enables automatic usage tracking via GitHub OIDC. Ask me if I would like to update the test-command if this project uses a test runner like "npx jest", "npx vitest", "npx playwright test".