feat: migrate runtime backend to node server

vite.config.ts

@@ -4,10 +4,11 @@ import tailwindcss from '@tailwindcss/vite';
 import react from '@vitejs/plugin-react';
 import {defineConfig, loadEnv} from 'vite';
 
-import {createLocalApiPlugins} from './scripts/dev-server/localApiPlugins';
-
 export default defineConfig(({mode}) => {
   const env = loadEnv(mode, __dirname, '');
+  const runtimeServerTarget =
+    env.NODE_SERVER_TARGET ||
+    'http://127.0.0.1:8081';
 
   return {
     root: __dirname,
@@ -15,7 +16,6 @@ export default defineConfig(({mode}) => {
     plugins: [
       react(),
       tailwindcss(),
-      ...createLocalApiPlugins(__dirname, mode, env),
     ],
     define: {
       'process.env.GEMINI_API_KEY': JSON.stringify(env.GEMINI_API_KEY),
@@ -29,6 +29,34 @@ export default defineConfig(({mode}) => {
       // HMR is disabled in AI Studio via DISABLE_HMR env var.
       // Do not modify; file watching is disabled to prevent flickering during agent edits.
       hmr: process.env.DISABLE_HMR !== 'true',
+      proxy: {
+        '/api/auth': {
+          target: runtimeServerTarget,
+          changeOrigin: true,
+          secure: false,
+        },
+        '/api/runtime': {
+          target: runtimeServerTarget,
+          changeOrigin: true,
+          secure: false,
+        },
+        '/api/custom-world/scene-image': {
+          target: runtimeServerTarget,
+          changeOrigin: true,
+          secure: false,
+        },
+        '/api/llm': {
+          target: runtimeServerTarget,
+          changeOrigin: true,
+          secure: false,
+        },
+        '/api/ws': {
+          target: runtimeServerTarget,
+          changeOrigin: true,
+          secure: false,
+          ws: true,
+        },
+      },
       watch: {
         ignored: ['**/dist/**', '**/dist_check/**', '**/dist_check_final/**', '**/dist_check_monster_position/**'],
       },