A misplaced machine is finally undoable by mouse. The REMOVE button sits
with the tabs rather than on a page, because it's a mode, not a machine, and
it has to be reachable from any page. It stays armed between clicks —
demolition is usually plural — and clicking open ground does nothing, so a
stray click never reads as a broken tool. Toast: "UNIT RECLAIMED. THE FLOOR
REMEMBERS."
LANE-RENDER: the hover hook is the __remove ghost sentinel. The UI has no
Renderer reference and the only channel to the ghost is selectedBuild(),
which main.ts feeds to setGhost — so while remove is armed, bus._sel reads
{def: '__remove', dir: 0}. Key the demolition tint off that def id. It's safe
because sim's place handler ignores unknown defs, so main.ts's click-to-place
fires a place for __remove and nothing happens; the UI dispatches the real
remove itself. Exported as REMOVE_DEF and pinned by a test.
A magic string shared between two lanes via a NOTES file is not a design;
contract request filed for UIBus.setGhostMode.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>