chore: Add ignore filter tests and improve ci

[yamadashy]

Overview:

This PR makes improvements to the GitHub Actions workflow and TypeScript code.

Changes:

1. GitHub Actions Workflow:

   • Changed npm i to npm ci for clean installation of dependencies.
   • Added matrix testing for multiple OSes (ubuntu-latest, windows-latest, macos-latest) and Node.js versions (16.x, 18.x, 20.x).
   • Added CI_OS environment variable to indicate the runner OS.

2. TypeScript Code:

   • Added IgnoreFilter type in gitignoreUtils.ts.
   • Updated ignoreFilter argument type to IgnoreFilter in packDirectory function.
   • Added new test cases for createIgnoreFilter function.

3. Test Coverage:

   • Included all files in the src directory in the coverage target in vite.config.mts.