feat: 前后端全量开发 v0.2

后端:
- 客户模块 CRUD+搜索 (api/services/repositories 分层)
- 合同模块: FG单号规则/意向单转正式单/订单创建自动快照客户信息
- 优化下料: FFD首递减装箱算法(利用率统计/余料/未排入清单)
前端 (Vue3+TS+Element Plus):
- 7页面: 登录/工作台/订单中心/合同/客户/样板库/优化下料
- 自研二维窗型画布渲染器: 解析drawing_data渲染玻璃区域/外框/
  扇开向标记/尺寸标注, 支持缩放平移复位
- 样板库与订单联动(用此样板下单自动带图纸)
- axios统一envelope拦截/登录守卫/付费墙提示
工程:
- SPA history 回退路由, 构建产物挂载后端
- 全接口回归 6/6 通过

frontend/src/router/index.ts

@@ -0,0 +1,31 @@
+/** 路由：登录守卫 + 主布局 */
+import { createRouter, createWebHistory } from 'vue-router'
+import { useAuthStore } from '../stores/auth'
+
+const router = createRouter({
+  history: createWebHistory(),
+  routes: [
+    { path: '/login', component: () => import('../views/LoginView.vue') },
+    {
+      path: '/',
+      component: () => import('../views/LayoutView.vue'),
+      children: [
+        { path: '', redirect: '/dashboard' },
+        { path: 'dashboard', component: () => import('../views/DashboardView.vue'), meta: { title: '工作台' } },
+        { path: 'orders', component: () => import('../views/OrdersView.vue'), meta: { title: '订单管理' } },
+        { path: 'contracts', component: () => import('../views/ContractsView.vue'), meta: { title: '合同管理' } },
+        { path: 'customers', component: () => import('../views/CustomersView.vue'), meta: { title: '客户管理' } },
+        { path: 'templates', component: () => import('../views/TemplatesView.vue'), meta: { title: '样板库' } },
+        { path: 'optimize', component: () => import('../views/OptimizeView.vue'), meta: { title: '优化下料' } },
+      ],
+    },
+  ],
+})
+
+router.beforeEach(to => {
+  const auth = useAuthStore()
+  if (to.path !== '/login' && !auth.isLogin) return '/login'
+  return true
+})
+
+export default router