editor: structure build-start/end cues + menu hover/click SFX (#378)

* wip sfx

* wip audios

* feat(editor): structure build-start/end cues + menu hover/click SFX

Sound design pass for the build/items experience:

- Split structure-build into a start cue (draft begins) and end cue
  (commit). Wall/fence fire start on the first click; slab/ceiling/zone
  tick start on every non-closing vertex; roof on the first corner.
- Doors and windows now use the structure-end cue on place + move;
  shelves use item-place instead.
- New menu_hover (round-robin retired in favour of a single sample) and
  menu_click cues wired to the Build/Items main categories, item-catalog
  tiles, the icon rail / tab bar, and the bottom action menu (via the
  shared ActionButton).
- Refresh item_pick / item_place / item_rotate samples; drop the
  now-unused numbered menu_hover variations.

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

* fix(editor): silence forEach return lint in updateSFXVolumes

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

* chore(editor): convert SFX wavs to mp3 to shrink assets

Re-encode all SFX samples as 128kbps mp3 (~94% smaller, transparent for
short UI cues) and point the player at the .mp3 sources. Drops the .wav
originals; the freshly converted item_pick/place/rotate.mp3 override the
older committed mp3s.

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

---------

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

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

@@ -349,7 +349,7 @@ const MoveDoorTool: React.FC<{ node: DoorNode }> = ({ node: movingDoorNode }) =>
       useLiveTransforms.getState().clear(movingDoorNode.id)
       useScene.temporal.getState().pause()
 
-      triggerSFX('sfx:item-place')
+      triggerSFX('sfx:structure-build')
       hideCursor()
       useViewer.getState().setSelection({ selectedIds: [placedId] })
       exitMoveMode()

packages/nodes/src/door/tool.tsx

@@ -323,7 +323,7 @@ const DoorTool: React.FC = () => {
       useScene.getState().createNode(node, event.node.id as AnyNodeId)
       useViewer.getState().setSelection({ selectedIds: [node.id] })
       useScene.temporal.getState().pause()
-      triggerSFX('sfx:item-place')
+      triggerSFX('sfx:structure-build')
       alignmentCandidates = collectAlignmentAnchors(useScene.getState().nodes, '')
       useAlignmentGuides.getState().clear()