fix(auth-service): 跳过无手机号/密码的系统账户CDC同步

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

backend/services/auth-service/src/infrastructure/messaging/cdc/legacy-user-cdc.consumer.ts

@@ -124,6 +124,18 @@ export class LegacyUserCdcConsumer implements OnModuleInit, OnModuleDestroy {
   }
 
   private async upsertLegacyUser(user: UnwrappedCdcUser, sequenceNum: bigint) {
+    // 跳过没有手机号的系统账户（user_id 1-5 通常是系统/测试账户）
+    if (!user.phone_number) {
+      this.logger.debug(`Skipped user ${user.user_id} (no phone number)`);
+      return;
+    }
+
+    // 跳过没有密码的账户
+    if (!user.password_hash) {
+      this.logger.debug(`Skipped user ${user.user_id} (no password)`);
+      return;
+    }
+
     try {
       await this.prisma.syncedLegacyUser.upsert({
         where: { legacyId: BigInt(user.user_id) },