feat(assets): 任务测试资产支持 DSL 搜索

任务详情「测试资产」接口/服务多时不好找。复用资产管理页的 DSL
搜索(字段自动补全 + 分页),搜索始终限定在当前任务范围内。

- 抽出共享组件 asset-dsl-search.tsx,资产页与任务页复用,UI/交互一致
- QueryDSL/CountDSL 增加 taskID 参数,taskID>0 时强制 AND $N = ANY(task_ids)
  并补 task 来源信息;即便 DSL 内写 task_id 也无法越出当前任务
- 任务资产 tab 接入搜索框:有 DSL 走 searchTaskAssets,否则走 taskAssets

Closes #107

server/assets.go

@@ -346,9 +346,12 @@ func (s *Server) listAssets(w http.ResponseWriter, r *http.Request) {
 			writeErr(w, http.StatusBadRequest, err.Error())
 			return
 		}
-		total, err = as.CountDSL(dsl, typ)
+		// task_id scopes the DSL search to a task's assets (the task detail
+		// "测试资产" search); 0 means the global asset view.
+		taskID, _ := strconv.ParseInt(q.Get("task_id"), 10, 64)
+		total, err = as.CountDSL(dsl, typ, taskID)
 		if err == nil && offset < total {
-			assets, err = as.QueryDSL(dsl, typ, limit, offset)
+			assets, err = as.QueryDSL(dsl, typ, taskID, limit, offset)
 		}
 	} else {
 		companyID, _ := strconv.ParseInt(q.Get("company_id"), 10, 64)