Composite GitHub Action to compare artifact file sizes

This action is a reusable combination of:

1. Downloading the previous/base artifact (via dawidd6/action-download-artifact)
2. Comparing it against your current build output path (file, directory, or simple glob pattern: *, ?, **) and writing a markdown report

Example usage:

- uses: KarbitsCode/artifact-comparer@main
  id: compare
  with:
    artifact-name: windows-latest-build
    path: ./out/**/*

The action outputs:

• comparison-result JSON with base/head total size and delta
• a GitHub Actions step summary table with per-file KB before/after and delta (NEW/REMOVED/±n KB)

Implementation notes:

• the downloaded base artifact directory is automatically cleaned up at the end of the composite action (if: always() cleanup step)
• comparer logic runs inline via actions/github-script (no action-local npm install/runtime dependencies)
• downloading artifacts requires a token with workflow permission actions: read (for example permissions: { actions: read }); by default this uses GITHUB_TOKEN, but you can pass a different token via the github-token input if the default token is too restricted