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/towers/PPTMasterTower.ts

@@ -1,5 +1,6 @@
 import type Phaser from 'phaser'
 import { TowerBase } from './TowerBase'
+import { AudioEngine } from '../AudioEngine'
 import type { EnemyBase } from '../enemies/EnemyBase'
 
 export class PPTMasterTower extends TowerBase {
@@ -12,6 +13,7 @@ export class PPTMasterTower extends TowerBase {
   }
 
   attackAoe(enemies: EnemyBase[]): void {
+    AudioEngine.getInstance().playPPTBlast()
     const rangePx = this.attackRange * this.cellW
     this.showAoeEffect(rangePx)
     for (const e of enemies) {