Wider Laravel Support

Fix broken dependency (#1)

• Update stechstudio/phpinfo from ^0.4.0 (removed tags) to ^0.6|^1.0
• Support both phpinfo v0.6 (Result) and v1.0 (PhpInfo) via duck-typed API

Filament v3, v4, and v5 support

• Broaden filament/filament to ^3.0|^4.0|^5.0
• Cross-version compatible Page class using getView() override, getDefaultSlug(), and covariant
  return types

Laravel 13 support

• Require PHP 8.3+ (needed by phpinfo ^0.6 and Laravel 13)
• Laravel 13 supported via Filament v5.4+

Automated testing

• 15 Pest tests covering phpinfo capture, page config, plugin registration, and service provider
• GitHub Actions CI: PHP 8.3/8.4 × Filament v3/v4/v5 × Laravel 11/12/13

Standalone Package

Let's spin this page off into its own standalone package.