- Remove RoomMediaLocalDataSource dependency from InMemoryMediaRepository;
libraries, movies, series, and episodes are now held in MutableStateFlows
- observeSeriesWithContent derives from _series flow via map {}
- updateWatchProgress mutates _movies / _episodes in-memory
- ensureSeriesContentLoaded checks and updates _series in-memory
- Reorganize Room package: move entities/DAOs from local/room to room/entity and room/dao
