…and scripts

- Replaced react-scripts with Vite for development and build processes.
- Updated package.json scripts to use Vite commands.
- Removed public/index.html and created a new index.html for Vite.
- Updated testing setup to use Vitest instead of Jest.
- Refactored test mocks to use Vitest's mocking capabilities.
- Added Storybook configuration for Vite.
- Created new stories for ChannelCard component.
- Updated WebSocketProvider to use Vite's environment variables.
- Added global setup for testing with Vitest.

- Implemented migration scripts to add rating-related fields to Videos, ChannelVideos, and Channels tables.
- Created a backfill migration to populate existing video ratings using yt-dlp metadata.
- Developed a backfill script for manual execution to update ratings for all videos.
- Enhanced the video, channel, and channel video models to include content_rating, age_limit, normalized_rating, and rating_source fields.
- Introduced a ratingMapper module to normalize ratings from YouTube/yt-dlp data.
- Updated NFO generation to include rating information for compatibility with Plex/Kodi.
- Added integration and unit tests for the new rating features and mapping logic.
- Modified video processing modules to handle rating metadata during video downloads and validations.

…s in frontend

…c implementation

…lint checks

…G ratings