fix(identity-service): regenerate avatar if missing during account recovery

When recovering account via mnemonic or phone, check if avatarUrl is null
and regenerate a new random avatar SVG if needed. This fixes the bug where
users see no avatar after recovering their account.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

backend/services/identity-service/src/application/commands/recover-by-mnemonic/recover-by-mnemonic.handler.ts

@@ -7,6 +7,7 @@ import { EventPublisherService } from '@/infrastructure/kafka/event-publisher.se
 import { BlockchainClientService } from '@/infrastructure/external/blockchain/blockchain-client.service';
 import { ApplicationError } from '@/shared/exceptions/domain.exception';
 import { RecoverAccountResult } from '../index';
+import { generateRandomAvatarSvg } from '@/shared/utils/random-identity.util';
 
 @Injectable()
 export class RecoverByMnemonicHandler {
@@ -40,6 +41,14 @@ export class RecoverByMnemonicHandler {
 
     this.logger.log(`Mnemonic verified successfully for account ${command.accountSequence}`);
 
+    // 如果头像为空，重新生成一个
+    let avatarUrl = account.avatarUrl;
+    if (!avatarUrl) {
+      this.logger.log(`Account ${command.accountSequence} has no avatar, generating new one`);
+      avatarUrl = generateRandomAvatarSvg();
+      account.updateProfile({ avatarUrl });
+    }
+
     account.addDevice(command.newDeviceId, command.deviceName);
     account.recordLogin();
     await this.userRepository.save(account);
@@ -57,7 +66,7 @@ export class RecoverByMnemonicHandler {
       userId: account.userId.toString(),
       accountSequence: account.accountSequence.value,
       nickname: account.nickname,
-      avatarUrl: account.avatarUrl,
+      avatarUrl,
       referralCode: account.referralCode.value,
       accessToken: tokens.accessToken,
       refreshToken: tokens.refreshToken,

backend/services/identity-service/src/application/commands/recover-by-phone/recover-by-phone.handler.ts

@@ -1,4 +1,4 @@
-import { Injectable, Inject } from '@nestjs/common';
+import { Injectable, Inject, Logger } from '@nestjs/common';
 import { RecoverByPhoneCommand } from './recover-by-phone.command';
 import { UserAccountRepository, USER_ACCOUNT_REPOSITORY } from '@/domain/repositories/user-account.repository.interface';
 import { AccountSequence, PhoneNumber } from '@/domain/value-objects';
@@ -7,9 +7,12 @@ import { RedisService } from '@/infrastructure/redis/redis.service';
 import { EventPublisherService } from '@/infrastructure/kafka/event-publisher.service';
 import { ApplicationError } from '@/shared/exceptions/domain.exception';
 import { RecoverAccountResult } from '../index';
+import { generateRandomAvatarSvg } from '@/shared/utils/random-identity.util';
 
 @Injectable()
 export class RecoverByPhoneHandler {
+  private readonly logger = new Logger(RecoverByPhoneHandler.name);
+
   constructor(
     @Inject(USER_ACCOUNT_REPOSITORY)
     private readonly userRepository: UserAccountRepository,
@@ -31,6 +34,14 @@ export class RecoverByPhoneHandler {
     const cachedCode = await this.redisService.get(`sms:recover:${phoneNumber.value}`);
     if (cachedCode !== command.smsCode) throw new ApplicationError('验证码错误或已过期');
 
+    // 如果头像为空，重新生成一个
+    let avatarUrl = account.avatarUrl;
+    if (!avatarUrl) {
+      this.logger.log(`Account ${command.accountSequence} has no avatar, generating new one`);
+      avatarUrl = generateRandomAvatarSvg();
+      account.updateProfile({ avatarUrl });
+    }
+
     account.addDevice(command.newDeviceId, command.deviceName);
     account.recordLogin();
     await this.userRepository.save(account);
@@ -49,7 +60,7 @@ export class RecoverByPhoneHandler {
       userId: account.userId.toString(),
       accountSequence: account.accountSequence.value,
       nickname: account.nickname,
-      avatarUrl: account.avatarUrl,
+      avatarUrl,
       referralCode: account.referralCode.value,
       accessToken: tokens.accessToken,
       refreshToken: tokens.refreshToken,