fix: 登录响应结构与 API 文档对齐

- LoginResponse 的 tokens 嵌入 tokens 对象，移除平铺的 accessToken/refreshToken
- user 移除 xpTotal/streakDays（文档中未定义）
- refreshJwt 同时返回 accessToken 和 refreshToken，复用 signTokens

src/services/auth/jwt.ts

@@ -18,15 +18,15 @@ export function buildLoginResponse(
   refreshToken: string,
 ): LoginResponse {
   return {
-    accessToken,
-    refreshToken,
     user: {
       id: user.id,
       nickname: user.nickname ?? null,
       avatarUrl: user.avatarUrl ?? null,
       tier: user.tier ?? 'free',
-      xpTotal: user.xpTotal ?? 0,
-      streakDays: user.streakDays ?? 0,
+    },
+    tokens: {
+      accessToken,
+      refreshToken,
     },
   };
 }
@@ -90,13 +90,7 @@ export async function findOrCreateHuawei(
   return buildLoginResponse(user, tokens.accessToken, tokens.refreshToken);
 }
 
-export async function refreshJwt(app: FastifyInstance, refreshToken: string): Promise<{ accessToken: string }> {
+export async function refreshJwt(app: FastifyInstance, refreshToken: string): Promise<{ accessToken: string; refreshToken: string }> {
   const decoded = app.jwt.verify<JwtPayload>(refreshToken);
-  const payload: JwtPayload = {
-    userId: decoded.userId,
-    authType: decoded.authType,
-    tier: decoded.tier,
-  };
-  const accessToken = app.jwt.sign(payload, { expiresIn: '1h' });
-  return { accessToken };
+  return signTokens(app, decoded.userId, decoded.authType, decoded.tier ?? 'free');
 }

src/types/auth.ts

@@ -8,15 +8,15 @@ export interface JwtPayload {
 }
 
 export interface LoginResponse {
-  accessToken: string;
-  refreshToken: string;
   user: {
     id: string;
     nickname: string | null;
     avatarUrl: string | null;
     tier: string;
-    xpTotal: number;
-    streakDays: number;
+  };
+  tokens: {
+    accessToken: string;
+    refreshToken: string;
   };
 }