fix: 后台加人人数改为事务内实际插入数

internal/app/group/app.go

@@ -620,7 +620,7 @@ func (a *App) AdminAddMembers(ctx context.Context, groupID string, memberIDs []s
 		failed = append(failed, MemberFail{ID: id, Code: protocol.CodeGroupFull})
 	}
 	if len(toAdd) == 0 {
-		return AddResult{Failed: failed}, nil
+		return AddResult{Failed: failed, Added: 0}, nil
 	}
 	now := a.nowMs()
 	var inserted []string
@@ -664,7 +664,7 @@ func (a *App) AdminAddMembers(ctx context.Context, groupID string, memberIDs []s
 	for _, id := range inserted {
 		a.emit(ctx, notify, groupID, eventMemberAdded, id, now)
 	}
-	return AddResult{Failed: failed}, nil
+	return AddResult{Failed: failed, Added: len(inserted)}, nil
 }
 
 func (a *App) createAdmin(ctx context.Context, ownerID, name, gid string, members []protocol.GroupMemberIn) (CreateResult, error) {