fix: 允许编辑进行中的拼团/秒杀活动及修复成团检测

- 移除拼团活动"进行中不能修改"限制
- 编辑拼团/秒杀时不再限制开始时间必须晚于当前
- 编辑时日期选择器不禁用过去日期
- 修复JPA缓存导致成团检测失效的问题(clearAutomatically)

src/main/java/com/org/flashsalesystem/repository/GroupBuyingGroupRepository.java

@@ -33,11 +33,11 @@ public interface GroupBuyingGroupRepository extends JpaRepository<GroupBuyingGro
 
     long countByGroupBuyingIdAndStatus(Long groupBuyingId, Integer status);
 
-    @Modifying
+    @Modifying(clearAutomatically = true)
     @Query("UPDATE GroupBuyingGroup g SET g.currentMembers = g.currentMembers + 1 WHERE g.id = :id")
     int incrementCurrentMembers(@Param("id") Long id);
 
-    @Modifying
+    @Modifying(clearAutomatically = true)
     @Query("UPDATE GroupBuyingGroup g SET g.currentMembers = g.currentMembers - 1 WHERE g.id = :id AND g.currentMembers > 0")
     int decrementCurrentMembers(@Param("id") Long id);
 

src/main/java/com/org/flashsalesystem/service/GroupBuyingService.java

@@ -109,10 +109,6 @@ public class GroupBuyingService {
         GroupBuying gb = groupBuyingRepository.findById(id)
                 .orElseThrow(() -> new RuntimeException("拼团活动不存在"));
 
-        if (gb.getStatus() == 2) {
-            throw new RuntimeException("进行中的活动不能修改");
-        }
-
         if (updateDTO.getProductId() != null) gb.setProductId(updateDTO.getProductId());
         if (updateDTO.getGroupPrice() != null) gb.setGroupPrice(updateDTO.getGroupPrice());
         if (updateDTO.getRequiredMembers() != null) gb.setRequiredMembers(updateDTO.getRequiredMembers());