docs: migrate documentation from VitePress to Starlight (#361)

- Replace VitePress with Astro Starlight for documentation
- Reorganize document structure with better hierarchy
- Split large documents into sub-modules for better readability
- Add new sections: component, entity-query, serialization, system
- Support both Chinese (default) and English documentation
- Add responsive design and improved navigation

docs/package.json

@@ -0,0 +1,21 @@
+{
+  "name": "docs-new",
+  "type": "module",
+  "version": "0.0.1",
+  "scripts": {
+    "dev": "astro dev",
+    "start": "astro dev",
+    "build": "astro build",
+    "preview": "astro preview",
+    "astro": "astro"
+  },
+  "dependencies": {
+    "@astrojs/starlight": "^0.37.1",
+    "@astrojs/vue": "^5.1.3",
+    "@tailwindcss/vite": "^4.1.18",
+    "astro": "^5.6.1",
+    "sharp": "^0.34.2",
+    "tailwindcss": "^4.1.18",
+    "vue": "^3.5.26"
+  }
+}