fix: align backend APIs and upload flow

GroupService.Domain/Entities/Group.cs

@@ -1,4 +1,4 @@
-using GroupService.Domain.Enums;
+using GroupService.Domain.Enums;
 using GroupService.Domain.Events;
 using IM.DomainCommons;
 
@@ -65,13 +65,15 @@ namespace GroupService.Domain.Entities
             AddDomainEvent(new AllMembersBannedDomainEvent(this));
         }
 
-        public void Ban()
+        public void Ban(bool notify = true)
         {
             Status = GroupState.Blocked;
             ModificationTime = DateTime.Now;
-            AddDomainEvent(new GroupBlockedDomainEvent(this));
+            if (notify) AddDomainEvent(new GroupBlockedDomainEvent(this));
         }
 
+        public void Unban() { Status = GroupState.Normal; ModificationTime = DateTime.Now; }
+
         public void Update(string? name, GroupAuthorityType? groupAuthority, string? announcement, string? avatar)
         {
             bool isChanged = false;

GroupService.Domain/Entities/GroupMember.cs

@@ -49,5 +49,12 @@ namespace GroupService.Domain.Entities
         {
             GroupNickName = nickname;
         }
+
+        public void Leave()
+        {
+            if (IsDeleted) return;
+            SoftDelete();
+            AddDomainEvent(new GroupMemberLeftDomainEvent(this));
+        }
     }
 }