✨ feat(contracts): 添加合同与客户的关联查询

- 在合同CRUD路由配置中添加relations字段，关联client信息
- 实现合同查询时自动关联查询客户数据，提升数据完整性

src/server/api/contracts/index.ts

@@ -9,6 +9,7 @@ const hetongRoutes = createCrudRoutes({
   updateSchema: UpdateHetongDto,
   getSchema: HetongSchema,
   listSchema: HetongSchema,
+  relations: ['client'],
   searchFields: ['contractNumber', 'clientId', 'status'],
   middleware: [authMiddleware]
 });