Compose sat at the bottom of the unfolded sidebar and also joined the
thread's actions in the vertical bar whenever the sidebar was hidden,
while the empty workspace offered a third New Task button.

The workspace navigator now owns compose for the Duo's detail column and
adds it to that column's bar as its own group. That bar is the vertical
bar when the Duo is folded or in landscape, so compose sits with the
detail column's actions on every Threads screen. The thread header stops
adding its own New task, the unfolded sidebar drops compose, and the
empty workspace drops its button when the bar already has compose. The
folded list keeps compose in its own bar. Pull requests leave compose
out on the Duo; their bar is already full of review actions.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>