feat: modernize codebase with async/await and updated dependencies

[tinsever]

• Remove async library dependency, replace with native async/await
• Remove mv package, use native fs.promises.rename()
• Update commander v2 -> v12 (latest)
• Update file-type v3 -> v19 (latest)
• Convert all callback-based code to async/await in:
  • lib/system-font.js
  • lib/google-font.js
  • lib/google-font-list.js
  • lib/request.js
• Maintain backward compatibility with callback APIs
• Use native Array methods instead of async library
• Use fs.promises instead of callback-based fs
• Update CLI to use new Commander API

BREAKING CHANGES:

• Requires Node.js 14+ for fs.promises and recursive mkdir
• Commander v12 requires new Command() syntax