feat(timer): 添加定时器和冷却系统 (#325)

- 添加 ITimerService 接口和 TimerService 实现
- 支持一次性定时器和重复定时器
- 支持冷却系统 (startCooldown/isCooldownReady/getCooldownProgress)
- 添加 8 个蓝图节点:
  - StartCooldown, IsCooldownReady, GetCooldownProgress
  - ResetCooldown, GetCooldownInfo
  - HasTimer, CancelTimer, GetTimerRemaining

packages/timer/tsconfig.json

@@ -0,0 +1,14 @@
+{
+    "extends": "../../tsconfig.base.json",
+    "compilerOptions": {
+        "composite": true,
+        "outDir": "./dist",
+        "rootDir": "./src"
+    },
+    "include": ["src/**/*"],
+    "exclude": ["node_modules", "dist"],
+    "references": [
+        { "path": "../core" },
+        { "path": "../blueprint" }
+    ]
+}