fix: 修复 getLunarFromSolar 导出问题

- 在 lunar.ts 中添加 getLunarFromSolar 函数导出
- 移除 countdown.ts 中的重复定义

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/utils/countdown.ts

@@ -286,15 +286,3 @@ export function getSolarFromLunar(lunarMonth: number, lunarDay: number, year?: n
   return new Date(solar.getYear(), solar.getMonth() - 1, solar.getDay());
 }
 
-/**
- * 获取公历日期的农历日期
- */
-export function getLunarFromSolar(solarDate: Date): { month: number; day: number; monthInChinese: string; dayInChinese: string } {
-  const lunar = Lunar.fromYmd(solarDate.getFullYear(), solarDate.getMonth() + 1, solarDate.getDate());
-  return {
-    month: lunar.getMonth(),
-    day: lunar.getDay(),
-    monthInChinese: lunar.getMonthInChinese(),
-    dayInChinese: lunar.getDayInChinese(),
-  };
-}

src/utils/lunar.ts

@@ -137,6 +137,19 @@ export function getDayGanZhi(date: Date): string {
   }
 }
 
+/**
+ * 获取公历日期的农历信息
+ */
+export function getLunarFromSolar(solarDate: Date): { month: number; day: number; monthInChinese: string; dayInChinese: string } {
+  const lunar = Lunar.fromYmd(solarDate.getFullYear(), solarDate.getMonth() + 1, solarDate.getDate());
+  return {
+    month: lunar.getMonth(),
+    day: lunar.getDay(),
+    monthInChinese: lunar.getMonthInChinese(),
+    dayInChinese: lunar.getDayInChinese(),
+  };
+}
+
 /**
  * 判断是否为农历节日
  */