- Split view: every pane shows the selected lane, each in its own tmux
session (`slot` 0-3 on POST /api/lanes/:id/start; slot 0 stays the
lane's `run_id`, slots 1-3 are `agenthub-lane-<id>-<slot>`). A pane's
Active runs hides what the other panes show; stop/reset/remove kill
every slot. No per-pane lane picker any more.
- Whole-file editor: PUT /api/lanes/:id/git/file (lane-file-write.js)
with the read path's guards, existing text files only, and a baseSha
stale check (409 ESTALE). A file it cannot take says why.
- Per-hunk review bar under each hunk's last changed line: prev/next,
"n of N", Undo, Keep. Review diffs no longer nest their own scroll box
(unless windowed), so navigation moves the one real scroller.
- Files tree lists untracked-not-ignored files and colours entries by git
status (M/U/A/D/R), folders holding changes get a dot.
- Changes panel: Unstage all on the single commit/Stage-all row; sizes
Narrow (30%) / Medium / Full screen, no 70/30.
- Lane card: the needs-you banner is gone (the strip tile keeps it).
