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>

apps/api/src/activities/activities.controller.ts

@@ -72,14 +72,14 @@ export class ActivitiesController {
 
   @Get('boards')
   listBoards(@CurrentUser() user: Actor) {
-    return this.stagesService.listBoards(user.organizationId);
+    return this.stagesService.listBoards(user.organizationId, user);
   }
 
   @Post('boards')
   @UseGuards(RolesGuard)
   @Roles('owner', 'admin')
   createBoard(@CurrentUser() user: Actor, @Body() dto: CreateActivityBoardDto) {
-    return this.stagesService.createBoard(user.organizationId, dto.name);
+    return this.stagesService.createBoard(user.organizationId, dto.name, dto.memberIds);
   }
 
   @Patch('boards/:id')
@@ -103,7 +103,7 @@ export class ActivitiesController {
 
   @Get('stages')
   listStages(@CurrentUser() user: Actor, @Query() query: ListActivityStagesQueryDto) {
-    return this.stagesService.list(user.organizationId, query.boardId);
+    return this.stagesService.list(user.organizationId, query.boardId, user);
   }
 
   @Post('stages')