feat: 新用户默认昵称及个人中心加载状态修复

- 新用户注册时随机生成普拉提主题默认昵称（16 个可选）
- 修复 App 启动后个人中心首次进入不展示用户信息的 bug
  - loggedIn 改为仅依赖 token 是否存在
  - 新增 hasProfile 判断用户数据是否已加载
  - 未加载时显示骨架屏而非空白
- 抽离随机函数为可注入依赖，消除 Math.random 测试耦合

packages/server/src/auth/__tests__/auth.service.spec.ts

@@ -2,7 +2,7 @@ import { Test, TestingModule } from '@nestjs/testing'
 import { JwtService } from '@nestjs/jwt'
 import { UnauthorizedException } from '@nestjs/common'
 import { UserRole } from '@mp-pilates/shared'
-import { AuthService } from '../auth.service'
+import { AuthService, RANDOM_FN_TOKEN } from '../auth.service'
 import { WechatService } from '../wechat.service'
 import { PrismaService } from '../../prisma/prisma.service'
 
@@ -12,13 +12,14 @@ const OPENID = 'test_openid_123'
 const SESSION_KEY = 'test_session_key'
 const USER_ID = 'user-uuid-001'
 const JWT_TOKEN = 'signed.jwt.token'
+const TEST_NICKNAME = '优雅普拉提'
 
 const mockUser = {
   id: USER_ID,
   openid: OPENID,
   unionid: null,
   phone: null,
-  nickname: '',
+  nickname: TEST_NICKNAME,
   avatarUrl: null,
   role: UserRole.MEMBER,
   createdAt: new Date(),
@@ -57,6 +58,7 @@ describe('AuthService', () => {
         { provide: PrismaService, useValue: mockPrismaService },
         { provide: WechatService, useValue: mockWechatService },
         { provide: JwtService, useValue: mockJwtService },
+        { provide: RANDOM_FN_TOKEN, useValue: () => 0 }, // deterministic nickname
       ],
     }).compile()
 
@@ -89,7 +91,7 @@ describe('AuthService', () => {
         where: { openid: OPENID },
       })
       expect(mockPrismaService.user.create).toHaveBeenCalledWith({
-        data: { openid: OPENID },
+        data: { openid: OPENID, nickname: TEST_NICKNAME },
       })
       expect(result.user).toEqual(mockUser)
     })
@@ -107,7 +109,7 @@ describe('AuthService', () => {
       await authService.login(loginCode)
 
       expect(mockPrismaService.user.create).toHaveBeenCalledWith({
-        data: { openid: OPENID, unionid },
+        data: { openid: OPENID, unionid, nickname: TEST_NICKNAME },
       })
     })