Added functionality to populate the Folder field in GetUser and GetUsers API responses
with the library IDs that the user has access to. This allows Subsonic API clients
to understand which music folders (libraries) a user can access for proper
content filtering and UI presentation.
Signed-off-by: Deluan <deluan@navidrome.org>
- Fix GetUser JukeboxRole to properly respect AdminOnly setting
- Extract buildUserResponse helper to eliminate duplication between GetUser and GetUsers
- Fix username field inconsistency (GetUsers was using loggedUser.Name instead of UserName)
- Add comprehensive tests covering jukebox role permissions and consistency between methods
Fixes#4160
