feat(editor): preset placement polish — params, move tool, shadows, isolation (#357)

* feat(editor): preset placement polish — params, move tool, shadows

- wall/slab/ceiling/roof create paths consume `toolDefaults` so template
  presets build with their saved params; cleared on tool unmount
- wall draw preview reflects the preset's height/thickness (+ HUD labels)
- box-select picks up registry-selectable kinds (shelf) via bbox
- registry + column move tools: snap to the active grid step, R/T rotation,
  and ignore the stray trailing click that armed the move (no double-place)
- shelf geometry casts + receives shadows like fence/slab

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

* feat(viewer): expose isIsolationActive() for isolation-aware consumers

Tracks whether an isolation filter is currently applied and exposes it so
hosts can avoid acting on the partial view — e.g. skipping project-thumbnail
autosave while a single subtree is isolated (preset capture).

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

---------

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

packages/nodes/src/shelf/geometry.ts

@@ -93,6 +93,13 @@ export function buildShelfGeometry(
       break
   }
 
+  // Boards/brackets cast + receive shadows like the other geometry-driven
+  // kinds (fence, slab). Set once here rather than on every `new Mesh` above.
+  for (const child of group.children) {
+    child.castShadow = true
+    child.receiveShadow = true
+  }
+
   return group
 }