feat: Add genres API endpoints

[ddx-510]

Summary

This PR adds comprehensive genre API support, allowing users to fetch genre lists and filter movies by single or multiple genres using JavBus's native format.

Features Added

• GET /api/genres - Get all genres with optional counts
• GET /api/genres/{genreId} - Get movies for a specific genre
• Support for multiple genre combinations using JavBus native format (e.g., /api/genres/62-4r for genres 62 AND 4r)

Changes Made

• Added getAllGenres() function to fetch and parse genre listings from /genre page
• Added getGenreMovies() function to fetch movies filtered by genre(s)
• Added genre router with endpoints
• Updated types to include Genre interface
• Exported baseMoviesPageValidator for reuse
• Updated README with complete genre API documentation

Example Usagesh

Get all genres

GET /api/genres

Get movies for a single genre

GET /api/genres/7w

Get movies matching multiple genres (JavBus native format)

GET /api/genres/62-4r## Testing

• ✅ Single genre filtering works
• ✅ Multiple genre combinations work (using JavBus dash-separated format)
• ✅ Genre listing works
• ✅ Documentation updated with examples

[vercel]

@ddx-510 is attempting to deploy a commit to the ovnrain's projects Team on Vercel.

A member of the Team first needs to authorize it.

[ovnrain]

I will review this PR when I have time. Please wait, and thank you for your support.