'Prepare' currently always transitions to 'play' in the GUI. The backend should send a confirmation that the GUI will receive, only transitioning to the 'play' mode when 'prepare' is successful.
Backend already sends a playing boolean to the GUI periodically. GUI should read the current state from the last status message received rather than maintaining its own state.
'Prepare' currently always transitions to 'play' in the GUI. The backend should send a confirmation that the GUI will receive, only transitioning to the 'play' mode when 'prepare' is successful.