The 2D build/edit tools republish the snapped cursor point AND the screen-space
coordinate-badge position on every pointer move. Both lived in FloorplanPanel
useState, so each move re-rendered the whole ~310ms panel (the badge fires on
every pointermove while any build tool is active — the dominant culprit).
Move both into a useFloorplanDraftPreview store written via getState() (no panel
re-render); render the crosshair + live polygon-draft edge from a
FloorplanDraftCursorLayer leaf and the coordinate badge from a
FloorplanCursorIndicator leaf, each subscribing to the store. Same store+leaf
pattern as the stair build preview. Slab/zone/ceiling drafts now have zero
per-move panel setState. Wall/fence/roof draftEnd are follow-up slices.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
