Dummy mirrored button used to balance title centering rendered as a
visible empty glass pill under iOS 26's automatic button chrome. Side
buttons now only render when actually configured, title centers via
ZStack independent of button widths, and title padding is derived from
measured button width so long titles truncate instead of overlapping.
Glass button style is opt-in via setGlassButtonsEnabled(_:), off by
default.
72a5b59c44