TMDB API key required

TMDB request failed (400): /discover/tv?sort_by=popularity.desc&page=544&with_original_language=ko

1. 1. Create a key at themoviedb.org/settings/api
2. 2. Copy .env.example to .env.local
3. 3. Set TMDB_API_KEY=your_key
4. 4. Restart the dev server