docs: Add Claude AI guidance and improve README (#11)

- Introduce CLAUDE.md to provide detailed guidance for Claude Code AI.
- Significantly enhance README.md content and structure:
  - Add a new "Features" section.
- Expand and clarify "Quick Start" and "Advanced Configuration"
examples.
  - Include a comprehensive "Configuration Options" table.
  - Update "Development" commands and add a "Contributing" section.
- Add `.claude` to .gitignore.

Update PHP version to 8.3 and bump package versions in composer.json (#8

)

Release v7 (#7)

Minimal PHP version is 7.4 (#4)

Fixed

Fixes

Update PHP deps (#3)

strict_types=1 (#2)

Update deps

Fixes