feat(spatial): 空间查询和索引系统 (#324)

* feat(spatial): 添加空间查询包

- ISpatialQuery: 空间查询接口
  - findInRadius, findInRect, findNearest, findKNearest
  - raycast, raycastFirst
  - IBounds, IRaycastHit, SpatialFilter 类型

- ISpatialIndex: 空间索引接口
  - insert, remove, update, clear, getAll

- GridSpatialIndex: 网格空间索引实现
  - 基于均匀网格的空间划分
  - 支持所有 ISpatialQuery 操作

- 工具函数
  - createBounds, isPointInBounds, boundsIntersect
  - distanceSquared, distance

* feat(spatial): 添加空间查询蓝图节点

- 添加 FindInRadius/FindInRect/FindNearest/FindKNearest 节点
- 添加 Raycast/RaycastFirst 射线检测节点
- 每个节点包含模板和执行器
- 使用 menuPath: ['Spatial', ...] 组织节点菜单

packages/spatial/tsconfig.build.json

@@ -0,0 +1,22 @@
+{
+    "compilerOptions": {
+        "target": "ES2020",
+        "module": "ES2020",
+        "moduleResolution": "bundler",
+        "lib": ["ES2020", "DOM"],
+        "outDir": "./dist",
+        "rootDir": "./src",
+        "strict": true,
+        "esModuleInterop": true,
+        "allowSyntheticDefaultImports": true,
+        "skipLibCheck": true,
+        "forceConsistentCasingInFileNames": true,
+        "declaration": true,
+        "declarationMap": true,
+        "resolveJsonModule": true,
+        "experimentalDecorators": true,
+        "emitDecoratorMetadata": true
+    },
+    "include": ["src/**/*"],
+    "exclude": ["node_modules", "dist"]
+}