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/views/TemplatesView.vue

@@ -0,0 +1,94 @@
+<template>
+  <div>
+    <el-card>
+      <div class="toolbar">
+        <el-select v-model="catelogId" placeholder="全部分类" clearable style="width:160px" @change="load">
+          <el-option v-for="c in catelogs" :key="c.id" :label="c.name" :value="c.id" />
+        </el-select>
+        <el-input v-model="name" placeholder="模板名称" clearable style="width:200px" @keyup.enter="load" />
+        <el-button type="primary" @click="load">查询</el-button>
+        <div style="flex:1" />
+        <span class="count">共 {{ total }} 套官方样板</span>
+      </div>
+      <div v-loading="loading" class="grid">
+        <div v-for="t in rows" :key="t.id" class="item" @click="preview(t)">
+          <el-image :src="t.pic_url" fit="contain" lazy class="pic" />
+          <div class="cap">{{ t.name || `样板#${t.id}` }}</div>
+        </div>
+      </div>
+      <el-pagination style="margin-top:12px; justify-content:center" background layout="total, prev, pager, next"
+                     :total="total" :page-size="page_size" v-model:current-page="page" @current-change="load" />
+    </el-card>
+
+    <el-dialog v-model="previewVisible" :title="current?.name || `样板#${current?.id}`" width="72%" top="4vh">
+      <div v-if="current" class="preview">
+        <div class="canvas-box">
+          <WindoorCanvas :drawing-data="current.drawing_data" />
+        </div>
+        <div class="meta">
+          <span>尺寸限制: {{ current.low_width }}-{{ current.high_width }} × {{ current.low_height }}-{{ current.high_height }} mm</span>
+          <span>引用次数: {{ current.times }}</span>
+          <el-button type="primary" size="small" @click="useInOrder">用此样板下单</el-button>
+        </div>
+      </div>
+    </el-dialog>
+  </div>
+</template>
+
+<script setup lang="ts">
+import { onMounted, ref } from 'vue'
+import { useRouter } from 'vue-router'
+import { api } from '../api'
+import WindoorCanvas from '../components/WindoorCanvas.vue'
+
+const router = useRouter()
+const rows = ref<any[]>([])
+const total = ref(0)
+const page = ref(1)
+const page_size = 48
+const name = ref('')
+const catelogId = ref<number | undefined>()
+const catelogs = ref<any[]>([])
+const loading = ref(false)
+const previewVisible = ref(false)
+const current = ref<any>(null)
+
+async function load() {
+  loading.value = true
+  try {
+    const qs = `page=${page.value}&page_size=${page_size}&name=${name.value}${catelogId.value ? `&catelog_id=${catelogId.value}` : ''}`
+    const d = await api<any>('get', `/api/windoor/templates?${qs}`)
+    rows.value = d
+    // 接口无分页元数据时按返回量估计
+    total.value = d.length === page_size ? (page.value - 1) * page_size + d.length + 1 : (page.value - 1) * page_size + d.length
+  } finally { loading.value = false }
+}
+
+async function preview(t: any) {
+  current.value = await api<any>('get', `/api/windoor/templates/${t.id}`)
+  previewVisible.value = true
+}
+
+function useInOrder() {
+  router.push({ path: '/orders', query: { template: current.value.id } })
+}
+
+onMounted(async () => {
+  const tree = await api<any[]>('get', '/api/windoor/catelogs')
+  catelogs.value = tree.flatMap(t => [t, ...((t.children ?? []) as any[])])
+  load()
+})
+</script>
+
+<style scoped>
+.toolbar { display: flex; gap: 10px; margin-bottom: 12px; align-items: center; }
+.count { color: #909399; font-size: 13px; }
+.grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); gap: 12px; min-height: 200px; }
+.item { border: 1px solid #e4e7ed; border-radius: 8px; padding: 8px; cursor: pointer; background: #fff;
+  transition: box-shadow .2s; display: flex; flex-direction: column; align-items: center; }
+.item:hover { box-shadow: 0 2px 12px rgba(0,0,0,.12); }
+.pic { width: 100%; height: 110px; }
+.cap { font-size: 12px; color: #606266; margin-top: 6px; text-align: center; }
+.preview .canvas-box { height: 60vh; border: 1px solid #e4e7ed; border-radius: 6px; overflow: hidden; }
+.preview .meta { display: flex; gap: 20px; margin-top: 10px; color: #606266; font-size: 13px; align-items: center; }
+</style>