Add environment configuration example, update .gitignore for additional files, and refactor Vite config to load environment variables. Remove obsolete settings and backup files.

vite.config.js

@@ -1,19 +1,25 @@
-import { defineConfig } from 'vite'
+import { defineConfig, loadEnv } from 'vite'
 import react from '@vitejs/plugin-react'
 
-export default defineConfig({
-  plugins: [react()],
-  server: {
-    port: process.env.VITE_PORT || 3001,
-    proxy: {
-      '/api': `http://localhost:${process.env.PORT || 3002}`,
-      '/ws': {
-        target: `ws://localhost:${process.env.PORT || 3002}`,
-        ws: true
+export default defineConfig(({ command, mode }) => {
+  // Load env file based on `mode` in the current working directory.
+  const env = loadEnv(mode, process.cwd(), '')
+  
+  
+  return {
+    plugins: [react()],
+    server: {
+      port: parseInt(env.VITE_PORT) || 3001,
+      proxy: {
+        '/api': `http://localhost:${env.PORT || 3002}`,
+        '/ws': {
+          target: `ws://localhost:${env.PORT || 3002}`,
+          ws: true
+        }
       }
+    },
+    build: {
+      outDir: 'dist'
     }
-  },
-  build: {
-    outDir: 'dist'
   }
 })