feat: support a frontend prefix from VITE_PREFIX env variable

static/vite.config.ts

@@ -1,7 +1,13 @@
-import { defineConfig } from 'vite'
+import { defineConfig, loadEnv } from 'vite'
 import vue from '@vitejs/plugin-vue'
 
 // https://vitejs.dev/config/
-export default defineConfig({
-  plugins: [vue()],
+export default defineConfig(({ mode }) => {
+  const env = loadEnv(mode, process.cwd())
+  const frontendPrefix = env.VITE_PREFIX ? env.VITE_PREFIX : "/"
+  console.log(`VITE_PREFIX:${env.VITE_PREFIX}, frontend_prefix:${frontendPrefix}, mode:${mode} ...`)
+  return {
+    plugins: [vue()],
+    base: frontendPrefix
+  }
 })