feat(activities): let a group show and limit its members

Empty membership stays open to the whole workspace; picking people restricts who can see that activity group.

Co-authored-by: Cursor <cursoragent@cursor.com>

packages/shared/src/index.ts

@@ -1584,14 +1584,18 @@ export interface ActivityBoardDto {
   name: string;
   isDefault: boolean;
   position: number;
+  /** خالی = گروه برای همهٔ اعضای محیط باز است */
+  memberIds: string[];
 }
 
 export interface CreateActivityBoardRequest {
   name: string;
+  memberIds?: string[];
 }
 
 export interface UpdateActivityBoardRequest {
   name?: string;
+  memberIds?: string[];
 }
 
 export interface ActivityStageDto {