Added
- UPnP embedded device discovery (sub-devices)
- FCast PlaybackError handling for better error reporting
- Full FCast protocol v3 opcode support

Fixed
- FCast casting not working on some receivers (missing metadata type)
- DLNA 404 with special characters in filenames
- Dialogs hidden by keyboard on some devices

Improved
- Real error messages on media file copy failures
- Filename sanitization for reliable HTTP serving
