- Call _load_series_into_memory() before NFO scan phases to sync DB
to SeriesApp memory, fixing missing NFO for recently resolved folders
- Add TMDB lookup for series without cached tmdb_id during NFO creation
- Add get_tmdb_client() factory and get_tmdb_image_base_url() helpers
- Fix: use get_tv_show_details instead of deprecated get_series_details
- Fix tests: mock _load_series_into_memory in NFO scan tests