fix(game): 修复格子正方形和图片尺寸问题，用setDisplaySize精确控制角色图片占一格

game/enemies/BossVP.ts

@@ -14,9 +14,9 @@ export class BossVP extends EnemyBase {
   ) {
     super(scene, pathPoints, 800, 40, 30, 150, 'enemy-boss')
     this.onDestroyTower = onDestroyTower
-    // 放大 BOSS
-    const bossScale = Math.min(this.cellW, this.cellH) / 128 * 1.3
-    this.imageSprite.setScale(bossScale)
+    // BOSS 放大到 1.3 个格子（跨格的威压感）
+    const bossSize = this.cellW * 1.3
+    this.imageSprite.setDisplaySize(bossSize, bossSize)
     this.imageSprite.setDepth(12)
     // BOSS 出现特效
     scene.cameras.main.flash(800, 255, 0, 0, false)

game/enemies/EnemyBase.ts

@@ -87,10 +87,10 @@ export abstract class EnemyBase {
       this.y = pathPoints[0].y
     }
 
-    // 用 AI 图片精灵，尺寸按格子缩放
+    // 用 AI 图片精灵，精确设为格子尺寸的 75%（怪物比塔小一点）
+    const enemySize = cellW * 0.75
     this.imageSprite = scene.add.image(this.x, this.y, spriteKey)
-    const scale = Math.min(cellW, cellH) / 128 * 0.75
-    this.imageSprite.setScale(scale)
+    this.imageSprite.setDisplaySize(enemySize, enemySize)
     this.imageSprite.setDepth(10)
 
     this.healthBar = scene.add.graphics()

game/enemies/OldEmployee.ts

@@ -6,9 +6,8 @@ export class OldEmployee extends EnemyBase {
   constructor(scene: Phaser.Scene, pathPoints: PathPoint[]) {
     super(scene, pathPoints, 150, 50, 8, 30, 'enemy-old')
     this.shieldCount = 3
-    // 老员工图片稍大
-    const scale = Math.min(this.cellW, this.cellH) / 128 * 0.9
-    this.imageSprite.setScale(scale)
+    // 老员工比普通怪略大（0.85 个格子）
+    this.imageSprite.setDisplaySize(this.cellW * 0.85, this.cellW * 0.85)
   }
 
   getQuote(): string { return getRandomQuote('OldEmployee') }