chore: 初始化前端仓库并迁移 admin-ui

- 创建 rui-frontend 前端仓库
- 迁移 admin-ui 管理后台
- 创建 cashier-mobile 和 customer-mobile 占位项目
- 配置 pnpm workspace

package.json

@@ -0,0 +1,26 @@
+{
+  "name": "rui-frontend",
+  "version": "1.0.0",
+  "description": "睿核科技前端项目集合",
+  "private": true,
+  "type": "module",
+  "scripts": {
+    "dev:admin": "pnpm --filter admin-ui dev",
+    "dev:cashier": "pnpm --filter cashier-mobile dev",
+    "dev:customer": "pnpm --filter customer-mobile dev",
+    "build:admin": "pnpm --filter admin-ui build",
+    "build:cashier": "pnpm --filter cashier-mobile build",
+    "build:customer": "pnpm --filter customer-mobile build",
+    "build:all": "pnpm -r build",
+    "lint": "pnpm -r lint",
+    "type-check": "pnpm -r type-check"
+  },
+  "devDependencies": {
+    "typescript": "^5.4"
+  },
+  "packageManager": "pnpm@8.15.0",
+  "engines": {
+    "node": ">=18.0.0",
+    "pnpm": ">=8.0.0"
+  }
+}