feat: newapi-dashboard 全栈项目初始化

为 new-api (LLM API 网关) 构建独立前端管理面板:
- React 18 + TypeScript + Vite + Ant Design 5 前端
- Node.js + Express + better-sqlite3 BFF 后端
- 登录页: 站点选择器 + UserID + AccessToken 认证
- 仪表盘: 用户信息、额度环形图、7天趋势图、模型饼图、令牌概览、日志时间线
- 账单页: 筛选日志表格、模型消耗柱状图、充值记录、CSV/PDF 导出(HMAC签名)
- 管理员站点管理: 站点 CRUD
- API 代理: 多站点切换，会话管理

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/index.ts

@@ -0,0 +1,27 @@
+import express from 'express'
+import cors from 'cors'
+import sitesRouter from './routes/sites.js'
+import authRouter from './routes/auth.js'
+import proxyRouter from './routes/proxy.js'
+import billingRouter from './routes/billing.js'
+
+const app = express()
+const PORT = 3001
+
+app.use(cors())
+app.use(express.json())
+
+app.get('/api/health', (_req, res) => {
+  res.json({ success: true, message: 'NewAPI Dashboard BFF running' })
+})
+
+app.use('/api/sites', sitesRouter)
+app.use('/api/auth', authRouter)
+app.use('/proxy', proxyRouter)
+app.use('/api/billing', billingRouter)
+
+app.listen(PORT, () => {
+  console.log(`BFF server running on http://localhost:${PORT}`)
+})
+
+export default app