docs(forecast-summary): 修正返回类型注释为Promise类型

src/api/forecast/forecast-summary.js

@@ -204,7 +204,7 @@ export const updateSalesForecastMain = async (data) => {
     data
   })
 }
- 
+
 /**
  * 获取预测汇总详情
  * @param {string|number} forecastSummaryId - 预测汇总ID
@@ -489,7 +489,7 @@ export const approveSalesForecastSummaryParticulars = async (data) => {
  * 对应后端：GET /api/blade-factory/api/factory/salesForecastSummary/byMonth
  * @param {number|string} year - 年份，例如 2025
  * @param {number|string} month - 月份，1-12 或 '01'-'12'
- * @returns {SalesForecastByMonthResponse} 响应（data: ForecastSummaryRecord[]）
+ * @returns {Promise<SalesForecastByMonthResponse>} 响应（data: ForecastSummaryRecord[]）
  * @example
  * const res = await getSalesForecastSummaryByMonth(2025, 12)
  */