Add React frontend for energy trading system

Implements React + TypeScript UI with Vite and Tailwind CSS.
Features dashboard with real-time WebSocket updates, backtesting
page, model management interface, trading controls, and settings.
Includes state management with Zustand, API integration with
Axios/TanStack Query, and interactive charts with Recharts.

frontend/vite.config.ts

@@ -0,0 +1,25 @@
+import { defineConfig } from 'vite';
+import react from '@vitejs/plugin-react';
+import path from 'path';
+
+export default defineConfig({
+  plugins: [react()],
+  resolve: {
+    alias: {
+      '@': path.resolve(__dirname, './src'),
+    },
+  },
+  server: {
+    port: 3000,
+    proxy: {
+      '/api': {
+        target: 'http://localhost:8000',
+        changeOrigin: true,
+      },
+      '/ws': {
+        target: 'ws://localhost:8000',
+        ws: true,
+      },
+    },
+  },
+});