Introduces a 4th profile-style id (cardBg) alongside the existing
background/stand/overlay triplet. The new id is meant to render a
background that fills the entire user info card on the client.
- HabboInfo: new InfostandCardBg field, loaded/saved with the
existing background ids; users.background_card_id column added
via sqlupdates/add_users_background_card_id.sql.
- ChangeInfostandBgEvent: reads a 4th int with bytesAvailable
guard to remain compatible with older clients.
- RoomUserDataComposer, RoomUsersComposer, UserProfileComposer:
append the cardBg int after the existing trio. Bot sections in
RoomUsersComposer pad an extra zero to keep field count consistent.