UX improvements and bug fixes.

Bug fix: No longer silently fail when audio capture fails on mobile
Bug fix: Subtitle track selector UI properly updates if opened while tracks are still loading
Enhancement: Source maps included in store release
Bug fix: Subtitle tracks of unknown language are detected on Emby
Enhancement: Jellyfin support
Bug fix: Subtitles from previous video do not linger if video source changes
Enhancement: Restore default subtitle width to "auto"
Bug fix: Fix audio getting progressively louder when recording audio