feat: 云账号编辑功能 + 通知渠道种子数据 + 修复mock.go编译错误

- 新增 PUT /cloud-accounts/:id 后端端点（UpdateCloudAccount handler + 路由注册）
- 前端 CloudAccountManager 添加编辑弹窗：复用创建表单，凭证留空保持不变
- 修复 scripts/mock.go 编译错误：补充缺失的 generateNotifyChannels 函数（5种通知渠道种子）
- 包含前序未提交的告警通知渠道 CRUD 后端API + AlertManager 通知配置前端UI

backend/internal/api/handlers/server.go

@@ -469,6 +469,70 @@ func (h *CloudAccountHandler) CreateCloudAccount(c *gin.Context) {
 	})
 }
 
+// UpdateCloudAccount 更新云账号
+// @Summary 更新云账号
+// @Description 更新指定云账号信息
+// @Tags 云账号
+// @Accept json
+// @Produce json
+// @Security Bearer
+// @Param id path int true "云账号ID"
+// @Param request body createCloudAccountRequest true "更新请求"
+// @Success 200 {object} models.Response{data=models.CloudAccount}
+// @Router /cloud-accounts/{id} [put]
+func (h *CloudAccountHandler) UpdateCloudAccount(c *gin.Context) {
+	id, _ := strconv.Atoi(c.Param("id"))
+	var req createCloudAccountRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, models.Response{
+			Code:    400,
+			Message: "请求参数错误: " + err.Error(),
+		})
+		return
+	}
+
+	var account models.CloudAccount
+	if err := h.db.First(&account, id).Error; err != nil {
+		c.JSON(http.StatusNotFound, models.Response{
+			Code:    404,
+			Message: "云账号不存在",
+		})
+		return
+	}
+
+	// 只在提供非空值时更新凭证字段
+	if strings.TrimSpace(req.Name) != "" {
+		account.Name = strings.TrimSpace(req.Name)
+	}
+	if strings.TrimSpace(req.Provider) != "" {
+		account.Provider = strings.TrimSpace(req.Provider)
+	}
+	if strings.TrimSpace(req.AccessKey) != "" {
+		account.AccessKey = req.AccessKey
+	}
+	if strings.TrimSpace(req.SecretKey) != "" {
+		account.SecretKey = req.SecretKey
+	}
+	if strings.TrimSpace(req.Status) != "" {
+		account.Status = strings.TrimSpace(req.Status)
+	}
+	account.MonthlyCost = req.MonthlyCost
+
+	if err := h.db.Save(&account).Error; err != nil {
+		c.JSON(http.StatusInternalServerError, models.Response{
+			Code:    500,
+			Message: "更新失败",
+		})
+		return
+	}
+
+	c.JSON(http.StatusOK, models.Response{
+		Code:    200,
+		Message: "更新成功",
+		Data:    account,
+	})
+}
+
 // DeleteCloudAccount 删除云账号
 // @Summary 删除云账号
 // @Description 删除指定云账号