editor: green/red placement box for shelf + tool sync for presets (#366)

* feat(editor): shelf placement validity box + sync tool for positioned presets

Give the generic move tool a green/red footprint box for shelf placement,
matching the GLB item cursor, and drop the vertical-arrow CursorSphere for
shelves. Box colour comes from canPlaceOnFloor; an invalid (red) drop is
refused unless Shift forces it, and R/T play the rotate sfx. Re-sync the box
transform on node change so a re-armed clone isn't left at the previous
rotation/position.

Extract the box wireframe geometry helpers into a shared
placement-box-geometry module reused by the item coordinator and the new
declarative PlacementBox component. Export the Tool type so host apps can set
the active tool for a positioned preset.

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

* chore: apply biome formatting + ignore generated next-env.d.ts

Format files that predate the current biome config (lineWidth 100, single
quotes, semicolons as-needed) so they stop showing as dirty on every checkout.
Formatting only — no behavior change.

Also exclude **/next-env.d.ts from biome: Next regenerates it (double quotes +
semicolon) on every build, so biome kept reformatting it into a perpetual dirty
diff. Ignoring it lets Next own the file.

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

---------

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

packages/core/src/services/index.ts

@@ -4,9 +4,9 @@ export {
   type AlignmentGuideAxis,
   type AnchorKind,
   bboxAnchors,
-  resolveAlignment,
   type ResolveAlignmentInput,
   type ResolveAlignmentResult,
+  resolveAlignment,
 } from './alignment'
 export {
   createDragSession,