feat(task): add batch delete and cancel API support

支持批量删除和取消任务的接口：
- deleteTask 接口支持 POST 方式传入 ids 数组
- cancelTask 接口支持 POST 方式传入 ids 数组
- 前端批量操作改为调用批量接口，减少请求数量

Co-Authored-By: AI

internal/router/task.go

@@ -138,49 +138,138 @@ func showFile(w http.ResponseWriter, r *http.Request) {
 }
 
 func deleteTask(w http.ResponseWriter, r *http.Request) {
-	taskIDStr := r.FormValue("id")
-	taskID, err := strconv.Atoi(taskIDStr)
-	if err != nil {
+	// 支持单个删除（GET 参数 id）和批量删除（POST 参数 ids）
+	var taskIDs []int
+
+	if r.Method == http.MethodPost {
+		defer r.Body.Close()
+		var body struct {
+			IDs []int `json:"ids"`
+		}
+		if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
+			util.Res{Success: false, Message: "参数错误"}.Write(w)
+			return
+		}
+		taskIDs = body.IDs
+	} else {
+		taskIDStr := r.FormValue("id")
+		taskID, err := strconv.Atoi(taskIDStr)
+		if err != nil {
+			util.Res{Success: false, Message: "参数错误"}.Write(w)
+			return
+		}
+		taskIDs = []int{taskID}
+	}
+
+	if len(taskIDs) == 0 {
 		util.Res{Success: false, Message: "参数错误"}.Write(w)
 		return
 	}
+
 	db := util.MustGetDB()
 	defer db.Close()
 
-	_task, err := task.GetTask(db, taskID)
-	if err == sql.ErrNoRows {
-		util.Res{Success: true, Message: "数据库中没有该条记录，所以本次操作被忽略，可以算作成功。"}.Write(w)
-		return
-	}
-	if err != nil {
-		util.Res{Success: false, Message: fmt.Sprintf("task.GetTask: %v", err)}.Write(w)
-		return
-	}
-	filePath := _task.FilePath()
-	err = os.Remove(filePath)
-	if err != nil && !os.IsNotExist(err) {
-		util.Res{Success: false, Message: fmt.Sprintf("文件删除失败 os.Remove: %v", err)}.Write(w)
-		return
+	// 批量删除结果
+	successCount := 0
+	failedTasks := []struct {
+		ID    int
+		Error string
+	}{}
+
+	for _, taskID := range taskIDs {
+		_task, err := task.GetTask(db, taskID)
+		if err == sql.ErrNoRows {
+			// 数据库中没有该条记录，忽略
+			successCount++
+			continue
+		}
+		if err != nil {
+			failedTasks = append(failedTasks, struct {
+				ID    int
+				Error string
+			}{ID: taskID, Error: fmt.Sprintf("获取任务失败: %v", err)})
+			continue
+		}
+		filePath := _task.FilePath()
+		err = os.Remove(filePath)
+		if err != nil && !os.IsNotExist(err) {
+			failedTasks = append(failedTasks, struct {
+				ID    int
+				Error string
+			}{ID: taskID, Error: fmt.Sprintf("文件删除失败: %v", err)})
+			continue
+		}
+
+		err = task.DeleteTask(db, taskID)
+		if err != nil {
+			failedTasks = append(failedTasks, struct {
+				ID    int
+				Error string
+			}{ID: taskID, Error: fmt.Sprintf("数据库删除失败: %v", err)})
+			continue
+		}
+		successCount++
 	}
 
-	err = task.DeleteTask(db, taskID)
-	if err != nil {
-		util.Res{Success: false, Message: fmt.Sprintf("task.DeleteTask: %v", err)}.Write(w)
-		return
+	if len(failedTasks) == 0 {
+		util.Res{Success: true, Message: fmt.Sprintf("成功删除 %d 个任务", successCount)}.Write(w)
+	} else {
+		util.Res{
+			Success: successCount > 0,
+			Message: fmt.Sprintf("成功删除 %d 个任务，失败 %d 个", successCount, len(failedTasks)),
+			Data:    failedTasks,
+		}.Write(w)
 	}
-	util.Res{Success: true, Message: "删除成功"}.Write(w)
 }
 
 func cancelTask(w http.ResponseWriter, r *http.Request) {
-	taskIDStr := r.FormValue("id")
-	taskID, err := strconv.ParseInt(taskIDStr, 10, 64)
-	if err != nil {
+	// 支持单个取消（GET 参数 id）和批量取消（POST 参数 ids）
+	var taskIDs []int64
+
+	if r.Method == http.MethodPost {
+		defer r.Body.Close()
+		var body struct {
+			IDs []int64 `json:"ids"`
+		}
+		if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
+			util.Res{Success: false, Message: "参数错误"}.Write(w)
+			return
+		}
+		taskIDs = body.IDs
+	} else {
+		taskIDStr := r.FormValue("id")
+		taskID, err := strconv.ParseInt(taskIDStr, 10, 64)
+		if err != nil {
+			util.Res{Success: false, Message: "参数错误"}.Write(w)
+			return
+		}
+		taskIDs = []int64{taskID}
+	}
+
+	if len(taskIDs) == 0 {
 		util.Res{Success: false, Message: "参数错误"}.Write(w)
 		return
 	}
-	if task.CancelTask(taskID) {
-		util.Res{Success: true, Message: "任务已取消"}.Write(w)
+
+	// 批量取消结果
+	successCount := 0
+	failedIDs := []int64{}
+
+	for _, taskID := range taskIDs {
+		if task.CancelTask(taskID) {
+			successCount++
+		} else {
+			failedIDs = append(failedIDs, taskID)
+		}
+	}
+
+	if len(failedIDs) == 0 {
+		util.Res{Success: true, Message: fmt.Sprintf("成功取消 %d 个任务", successCount)}.Write(w)
 	} else {
-		util.Res{Success: false, Message: "任务不存在或已完成"}.Write(w)
+		util.Res{
+			Success: successCount > 0,
+			Message: fmt.Sprintf("成功取消 %d 个任务，失败 %d 个", successCount, len(failedIDs)),
+			Data:    failedIDs,
+		}.Write(w)
 	}
 }