实现消息记录功能，包括增删改查和标记已读，优化消息列表展示和未读消息计数

Service/MessageRecordService.cs

@@ -0,0 +1,68 @@
+namespace Service;
+
+public interface IMessageRecordService
+{
+    Task<(IEnumerable<MessageRecord> List, long Total)> GetPagedListAsync(int pageIndex, int pageSize);
+    Task<MessageRecord?> GetByIdAsync(long id);
+    Task<bool> AddAsync(MessageRecord message);
+    Task<bool> AddAsync(string title, string content);
+    Task<bool> MarkAsReadAsync(long id);
+    Task<bool> MarkAllAsReadAsync();
+    Task<bool> DeleteAsync(long id);
+    Task<long> GetUnreadCountAsync();
+}
+
+public class MessageRecordService(IMessageRecordRepository messageRepo) : IMessageRecordService
+{
+    public async Task<(IEnumerable<MessageRecord> List, long Total)> GetPagedListAsync(int pageIndex, int pageSize)
+    {
+        return await messageRepo.GetPagedListAsync(pageIndex, pageSize);
+    }
+
+    public async Task<MessageRecord?> GetByIdAsync(long id)
+    {
+        return await messageRepo.GetByIdAsync(id);
+    }
+
+    public async Task<bool> AddAsync(MessageRecord message)
+    {
+        return await messageRepo.AddAsync(message);
+    }
+
+    public async Task<bool> AddAsync(string title, string content)
+    {
+        var message = new MessageRecord
+        {
+            Title = title,
+            Content = content,
+            IsRead = false
+        };
+        return await messageRepo.AddAsync(message);
+    }
+
+    public async Task<bool> MarkAsReadAsync(long id)
+    {
+        var message = await messageRepo.GetByIdAsync(id);
+        if (message == null) return false;
+        
+        message.IsRead = true;
+        message.UpdateTime = DateTime.Now;
+        return await messageRepo.UpdateAsync(message);
+    }
+
+    public async Task<bool> MarkAllAsReadAsync()
+    {
+        return await messageRepo.MarkAllAsReadAsync();
+    }
+
+    public async Task<bool> DeleteAsync(long id)
+    {
+        return await messageRepo.DeleteAsync(id);
+    }
+
+    public async Task<long> GetUnreadCountAsync()
+    {
+        var list = await messageRepo.GetAllAsync();
+        return list.Count(x => !x.IsRead);
+    }
+}