The workspace trigger refused to shrink, so a large interface font made it
overflow and paint over the branch name. Every control now truncates, which
makes overlap impossible; icons-only remains the backstop for when even
truncated content cannot fit.

The overlap measurement had three faults: it summed flex-stretched boxes
(always 'full', so it always wanted to collapse), it counted a Base UI
hidden form element as 223px of phantom content, and the compiler-memoized
useEffectEvent left observers reading the first render's null element
forever. It now sums laid-out content (skipping hidden artifacts and the
absolutely-positioned compact labels, which stay measurable at natural
width), reads state through a render-synced ref, and applies hysteresis so
the boundary cannot flap.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>