feat(routes): restructure URLs with SEO-friendly slugs for shows, seasons, and episodes
- Change show URLs from /show/$id to /shows/[showId]/[showName]
- Change movie URLs from /movie/$id to /movies/[movieId]/[movieName]
- Add new episode detail page at /shows/[showId]/[showName]/seasons/[season]/episodes/[episode]
- Add new season detail page at /shows/[showId]/[showName]/seasons/[season]
- Create URL utility functions (slugifyName, buildShowUrl, buildMovieUrl, buildSeasonUrl, buildEpisodeUrl)
- Update MediaCard to support episode and season links
- Update dashboard, calendar, and search to use new URL format
- Install slugify package for consistent URL slugs
- Routes render as standalone pages (not nested within show detail)