feat: initialize Gradle multi-module backend and Vite frontend

frontend/packages/admin/vite.config.ts

@@ -0,0 +1,15 @@
+import { defineConfig } from 'vite'
+import vue from '@vitejs/plugin-vue'
+
+export default defineConfig({
+  plugins: [vue()],
+  server: {
+    port: 5173,
+    proxy: {
+      '/api': {
+        target: 'http://localhost:8080',
+        changeOrigin: true
+      }
+    }
+  }
+})