- Replace hardcoded 4-tab system with data-driven visible tab list
- Shared libraries show only Browse + Playlists tabs
- Fix dpad navigation for shared libraries (no hidden tab targets)
- Switch to TickerProviderStateMixin to support tab controller recreation
- Navigate to library screen when tapping shared library sections
- Persist tab selection by name instead of index
Plex API returns Directory entries without type field, causing
TypeError crash in fromJson. Made fields nullable and migrated
callers to use mediaType enum and displayTitle getter instead
of raw string access.
edde746