feat: v0.3 报价算料引擎与仓库库存模块

后端:
- 报价算料: 从drawing_data几何提取型材清单(外框/中梃/扇框投影长度)
  与玻璃面积(鞋带公式), 套价格本计价, 支持样板/订单/自定义图纸三入口
- 仓库库存: 材料CRUD/出入库/流水/负库存拦截/预警线
- SQLite默认路径锚定项目根目录(修复cwd依赖)
前端:
- 仓库库存页(筛选/出入库对话框/预警高亮)
- 算料报价弹窗(样板库与订单详情入口, 支持打印)
- 路由与导航更新(8页面)
回归: 9个API端点全部200, 报价/优化/SPA路由验证通过

frontend/src/views/TemplatesView.vue

@@ -28,10 +28,12 @@
         <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="success" size="small" @click="quoteRef.open({ template_id: current.id })">算料报价</el-button>
           <el-button type="primary" size="small" @click="useInOrder">用此样板下单</el-button>
         </div>
       </div>
     </el-dialog>
+    <QuoteDialog ref="quoteRef" />
   </div>
 </template>
 
@@ -40,8 +42,10 @@ import { onMounted, ref } from 'vue'
 import { useRouter } from 'vue-router'
 import { api } from '../api'
 import WindoorCanvas from '../components/WindoorCanvas.vue'
+import QuoteDialog from '../components/QuoteDialog.vue'
 
 const router = useRouter()
+const quoteRef = ref()
 const rows = ref<any[]>([])
 const total = ref(0)
 const page = ref(1)