feat(game/towers): TowerBase 添加 isFrozen 禁锢状态支持，禁锢时显示灰色覆盖层并跳过攻击

game/towers/TowerBase.ts

@@ -9,6 +9,7 @@ export abstract class TowerBase {
   public gridY: number
   protected sprite!: Phaser.GameObjects.Graphics
   protected staminaBar!: Phaser.GameObjects.Graphics
+  private frozenOverlay!: Phaser.GameObjects.Graphics
 
   public readonly cost: number
   public readonly attackRange: number
@@ -16,6 +17,7 @@ export abstract class TowerBase {
   public readonly attackSpeed: number
   public readonly maxStamina: number = STAMINA_MAX
   public stamina: number = STAMINA_MAX
+  public isFrozen: boolean = false
 
   protected attackCooldown: number = 0
   protected staminaRegen: number = STAMINA_REGEN
@@ -47,12 +49,20 @@ export abstract class TowerBase {
 
     this.sprite = scene.add.graphics()
     this.staminaBar = scene.add.graphics()
+    this.frozenOverlay = scene.add.graphics()
 
     this.drawSprite()
     this.updateStaminaBar()
   }
 
   update(delta: number, enemies: EnemyBase[]): void {
+    // 禁锢状态：跳过攻击，显示灰色覆盖
+    if (this.isFrozen) {
+      this.drawFrozenOverlay()
+      return
+    }
+    // 解除禁锢时清除覆盖层
+    this.clearFrozenOverlay()
     this.attackCooldown -= delta
 
     if (this.stamina <= 0) {
@@ -135,11 +145,31 @@ export abstract class TowerBase {
     return { x: this.px, y: this.py }
   }
 
+  /** 绘制禁锢状态灰色覆盖层 */
+  protected drawFrozenOverlay(): void {
+    this.frozenOverlay.clear()
+    const half = TILE_SIZE / 2
+    this.frozenOverlay.fillStyle(0x6b7280, 0.6)
+    this.frozenOverlay.fillRect(
+      this.px - half,
+      this.py - half,
+      TILE_SIZE,
+      TILE_SIZE
+    )
+    this.frozenOverlay.setDepth(13)
+  }
+
+  /** 清除禁锢覆盖层 */
+  protected clearFrozenOverlay(): void {
+    this.frozenOverlay.clear()
+  }
+
   abstract attack(target: EnemyBase): void
   abstract drawSprite(): void
 
   destroy(): void {
     this.sprite?.destroy()
     this.staminaBar?.destroy()
+    this.frozenOverlay?.destroy()
   }
 }