fix: handle duplicate usernames and failed role lookups in importDingTalkUsers

apps/server/src/sync/sync.service.ts

@@ -138,7 +138,7 @@ export class SyncService {
       }
 
       try {
-        const username = u.mobile || `dd_${u.dingUserId}`;
+        const username = `dd_${u.dingUserId}`;
         const passwordHash = await bcrypt.hash('123456', 10);
 
         const user = this.userRepo.create({
@@ -155,10 +155,18 @@ export class SyncService {
           if (role) {
             user.roles = [role];
             await this.userRepo.save(user);
+            teacherCount++;
           } else {
-            this.logger.warn(`角色 id=${u.roleId} 不存在，用户 ${u.name} 未分配角色`);
+            this.logger.warn(`角色 id=${u.roleId} 不存在，用户 ${u.name} 转为学生`);
+            const student = this.studentRepo.create({
+              name: u.name,
+              phone: u.mobile || undefined,
+              userId: user.id,
+              status: 'active',
+            });
+            await this.studentRepo.save(student);
+            studentCount++;
           }
-          teacherCount++;
         } else {
           // 学生：创建 Student 记录
           const student = this.studentRepo.create({