修复管理端团队成员列表不包含指导老师

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/src/contests/teams/teams.service.ts

@@ -284,6 +284,9 @@ export class TeamsService {
           },
         },
         members: {
+          where: {
+            role: { in: ['leader', 'member'] }, // 只查询队长和队员，不包含指导老师
+          },
           include: {
             user: {
               select: {