feat(editor): preset-system polish — paint panel, slim action bar, icon rail (#354)

* feat(editor): preset-system polish — paint panel, slim action bar, icon rail

- Export `MaterialPaintPanel` so embedders host the paint material picker in
  their own panel (community docks it in the Build sidebar) instead of the
  bottom action bar.
- ActionMenu: drop the build / material-paint / furnish modes and the
  structure-tools palette row + paint tray (the host's Build sidebar owns
  building now). Reduce `structure-tools` to the shared `tools` lookup still
  used by cursor/floorplan indicators; remove the orphaned `useContextualTools`.
- MaterialPicker: swatches wrap into a fluid `auto-fill` grid that fills width.
- IconRail (tab-bar): bigger icons, grayscale-when-idle, Radix tooltip, w-14
  rail; sync `RAIL_WIDTH` to 56.
- Inspector footer: hand the host `footer` to kind-owned custom panels via
  `InspectorFooterContext` so the save button renders without per-kind wiring.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* chore: biome format pass

Whole-repo formatter normalization (line wrap/unwrap only, no logic changes)
surfaced by the format-on-edit hook against prior drift. Kept separate from the
feature commit so the preset-system diff stays reviewable.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

packages/nodes/src/wall/move-tool.tsx

@@ -460,9 +460,7 @@ export const MoveWallTool: React.FC<{ node: WallNode }> = ({ node }) => {
       if (axis) {
         const originalProj = originalCenter[0] * axis[0] + originalCenter[1] * axis[1]
         const rawProj = originalProj + rawDeltaX * axis[0] + rawDeltaZ * axis[1]
-        const snappedProj = shiftPressedRef.current
-          ? rawProj
-          : snapScalarToGrid(rawProj, snapStep)
+        const snappedProj = shiftPressedRef.current ? rawProj : snapScalarToGrid(rawProj, snapStep)
         const perpDelta = snappedProj - originalProj
         deltaX = axis[0] * perpDelta
         deltaZ = axis[1] * perpDelta