重构项目结构，移除旧Java客户端，添加前后端目录

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/vite.config.js

@@ -0,0 +1,12 @@
+import { defineConfig } from 'vite'
+import vue from '@vitejs/plugin-vue'
+
+// https://vite.dev/config/
+export default defineConfig({
+  plugins: [vue()],
+  server: {
+    proxy: {
+      '/api': { target: 'http://localhost:8080', changeOrigin: true }
+    }
+  }
+})