feat(game): 添加全套音效系统（背景BGM+7种攻击音+波次/Boss/死亡/建塔音效），纯Web Audio API合成

game/enemies/BossVP.ts

@@ -1,6 +1,7 @@
 import type Phaser from 'phaser'
 import { EnemyBase, type PathPoint } from './EnemyBase'
 import { getRandomQuote } from '../data/quotes'
+import { AudioEngine } from '../AudioEngine'
 
 export class BossVP extends EnemyBase {
   private skillTimer: number = 20000
@@ -20,6 +21,8 @@ export class BossVP extends EnemyBase {
     this.imageSprite.setDisplaySize(bossSize, bossSize)
     this.imageSprite.setDepth(12)
     scene.cameras.main.flash(800, 255, 0, 0, false)
+    // Boss 登场音效
+    AudioEngine.getInstance().playBossAppear()
     this.showBossAlert()
     this.bossLabel = scene.add.text(this.x, this.y + this.cellH * 0.5, '空降VP', {
       fontFamily: 'VT323, monospace', fontSize: '14px',
@@ -55,6 +58,8 @@ export class BossVP extends EnemyBase {
 
   private triggerOrgRestructure(): void {
     this.onDestroyTower?.()
+    // Boss 技能音效
+    AudioEngine.getInstance().playBossSkill()
     const txt = this.scene.add
       .text(this.x, this.y - 40, '组织架构调整！', {
         fontFamily: 'VT323, monospace', fontSize: '18px',