feat(challenges): add vip user restrictions for challenge creation

限制非会员用户只能创建一个未归档的自定义挑战，添加用户VIP状态检查和挑战数量限制逻辑

src/challenges/challenges.service.ts

@@ -856,6 +856,29 @@ export class ChallengesService {
       throw new BadRequestException('无效的时间戳');
     }
 
+    // 获取用户信息，检查会员状态
+    const user = await User.findByPk(userId);
+    if (!user) {
+      throw new NotFoundException('用户不存在');
+    }
+
+    // 检查非会员用户已创建的未归档挑战数量
+    if (!user.isVip) {
+      const existingChallengeCount = await this.challengeModel.count({
+        where: {
+          creatorId: userId,
+          source: ChallengeSource.CUSTOM,
+          challengeState: {
+            [Op.ne]: ChallengeState.ARCHIVED, // 不包含已归档的挑战
+          },
+        },
+      });
+
+      if (existingChallengeCount >= 1) {
+        throw new BadRequestException('非会员用户只能创建一个挑战，您可以先归档现有挑战或升级会员');
+      }
+    }
+
     // 检查创建频率限制（每天最多创建 5 个）
     const recentCount = await this.challengeModel.count({
       where: {
@@ -908,6 +931,8 @@ export class ChallengesService {
       userId,
       challengeId: challenge.id,
       shareCode,
+      isVip: user.isVip,
+      existingChallengeCount: user.isVip ? null : 1,
     });
 
     return this.buildCustomChallengeResponse(challenge, userId);