feat: Add Filament Themer Luncher plugin

[AlizHarb]

Overview

This PR adds the Filament Themer Luncher plugin to the Filament marketplace. This plugin provides a comprehensive UI and suite of tools for managing themes within Filament, powered by the alizharb/laravel-themer engine.

✨ Features

• Theme Discovery & Management: Easily scan for and toggle themes directly from the admin panel.
• Backup & Recovery: Built-in functionality to create and restore theme backups.
• Developer Tools: Widgets and infolists specifically designed for clear theme status tracking.
• Multilingual Support: Fully localized in 11 languages.
• Premium Aesthetics: Designed to feel native to Filament with professional, glassmorphic UI elements.

📦 Package Information

• Repository: AlizHarb/filament-themer-luncher
• Composer: alizharb/filament-themer-luncher
• License: MIT

✅ Checklist

• Documentation added in content/plugins/
• High-resolution banner added in content/plugins/images/
• Correct naming conventions followed (alizharb-themer-luncher)