perf: 调整公告加载与排序逻辑，优化有效公告优先级展示

Yi.Abp.Net8/module/ai-hub/Yi.Framework.AiHub.Application/Services/AnnouncementService.cs

@@ -53,13 +53,23 @@ public class AnnouncementService : ApplicationService, IAnnouncementService
     /// </summary>
     private async Task<AnnouncementCacheDto> LoadAnnouncementDataAsync()
     {
-        // 查询所有公告日志，按日期降序排列
+        // 1️⃣ 一次性查出全部公告（不排序）
         var logs = await _announcementRepository._DbQueryable
-            .OrderByDescending(x => x.StartTime)
             .ToListAsync();
 
+        var now = DateTime.Now;
+
+        // 2️⃣ 内存中处理排序
+        var orderedLogs = logs
+            .OrderByDescending(x =>
+                x.StartTime <= now &&
+                (x.EndTime == null || x.EndTime >= now)
+            )
+            .ThenByDescending(x => x.StartTime)
+            .ToList();
+
         // 转换为 DTO
-        var logDtos = logs.Adapt<List<AnnouncementLogDto>>();
+        var logDtos = orderedLogs.Adapt<List<AnnouncementLogDto>>();
         return new AnnouncementCacheDto
         {
             Logs = logDtos