Where did the isolation button go?

Its jobs moved closer to what they act on. Creating an isolated shard now uses the worktree button in the shard bar (or the File menu). Merging and rebasing are now on each shard’s tab: a shard with unmerged commits shows a small ↑N badge you can click, and every action names the branch, target, and commit count. A branches button appears whenever the gem has isolated work to show, live shards or parked branches, so you can reattach, merge, or discard parked work.