At a flag the game is over and togglePause is inert anyway — pauseNow
needs RUN, resumeNow needs PAUSE — so the button was there without being
able to do anything. It joins the other two visibility rules in render():
vacant at IDLE or FLAG. Reset stays, being the way out of a finished
game, and the bar comes down to Reset, score and sound.
Checked the whole state machine: shown while running and while paused,
vacant before a game's first tap and at a flag, and pausing and resuming
still work.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>