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>

apps/editor/components/build-tab.tsx

@@ -1,6 +1,6 @@
 'use client'
 
-import { MaterialPaintPanel, useEditor } from '@pascal-app/editor'
+import { MaterialPaintPanel, triggerSFX, useEditor } from '@pascal-app/editor'
 import Image from 'next/image'
 import { useCallback, useEffect, useRef } from 'react'
 import {
@@ -131,7 +131,11 @@ export function BuildTab() {
                         ? 'bg-primary/10 ring-1 ring-primary/50'
                         : 'bg-muted/40 opacity-70 grayscale hover:bg-muted hover:opacity-100 hover:grayscale-0',
                     )}
-                    onClick={() => handleTypeClick(type)}
+                    onClick={() => {
+                      triggerSFX('sfx:menu-click')
+                      handleTypeClick(type)
+                    }}
+                    onMouseEnter={() => triggerSFX('sfx:menu-hover')}
                     type="button"
                   >
                     <Image