fix(GUI): tab-bar sound, shared-timer block, arrow OnTop

Card c82304 (both analyst corrections honored).

• DrawTabBar: COMMAND_PlayEffect on tab switch — was silent (correction 1: ConsumeClick was already present)
• TabBar BUTTONBLOCKTIME 0.75 → 0.25 on shared 'Main' — arrow steps were locking all Main-gated controls 0.75s vs the ~0.2-0.3s convention
• drawArrows now forwards its existing OnTop to both DrawArrowButton calls (correction 2: the param existed on main; #1336 never touched DrawArrowButton)