Update dependencies and improve CLI documentation in README

[fabiomartino]

This PR introduces two main improvements:

1. Dependency Updates

• Updated several development and runtime dependencies to their latest compatible versions.
• Raised the Node.js engine requirement to >=16.0.0 to ensure compatibility with modern tools like Prettier 3 and Sharp 0.32.
• Fixed TypeScript 4.9+ compatibility issues (notably with error type guards in subprocess.ts).

2. Improved Documentation

• Updated README.md to reflect current implemented features:

  • Documented all supported CLI flags: --dark, --platform, --icon-only, --splash-only, etc.
  • Clarified Easy Mode vs Custom Mode workflows.
  • Described manifest handling and fallback paths for PWA.
  • Matched directory outputs with actual generated structure.

• This update brings the README in sync with both the CLI behavior and the Capacitor site documentation.

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Let me know if you want a shorter or more technical version.

[jhash]

Would love to see this merged! This would solve this security vulnerability in tar-fs for us:
GHSA-8cj5-5rvv-wf4v

Just started working on it myself before seeing this PR. Thank you for putting it together @fabiomartino