refactor(data): consolidate data layer under services namespace

- Move src/data/{api,dto,schemas} directories to src/data/services/*
- Update all relative imports across the codebase to reference new paths
- Use CSS color tokens for splash button gradient in splash-button.module.css
- Add responsive sizes attribute to splash background image
- Add JSDoc documentation to splash-background component referencing original Dart implementation

src/data/services/api/auth_api.ts

@@ -0,0 +1,152 @@
+/**
+ * Auth API
+ *
+ * 认证相关接口
+ * 原始 Dart: lib/data/services/api/auth_api_client.dart
+ */
+import { httpClient } from "./http_client";
+import { ApiPath } from "./api_path";
+import { ApiEnvelope, unwrap } from "./response_helper";
+import { AppleLoginRequest } from "@/data/dto/auth/apple_login_request";
+import { FacebookLoginRequest } from "@/data/dto/auth/facebook_login_request";
+import { FbIdLoginRequest } from "@/data/dto/auth/fb_id_login_request";
+import { GoogleLoginRequest } from "@/data/dto/auth/google_login_request";
+import { GuestLoginRequest } from "@/data/dto/auth/guest_login_request";
+import { GuestLoginResponse } from "@/data/dto/auth/guest_login_response";
+import { LoginRequest } from "@/data/dto/auth/login_request";
+import { LoginResponse } from "@/data/dto/auth/login_response";
+import { LogoutResponse } from "@/data/dto/auth/logout_response";
+import { RefreshTokenRequest } from "@/data/dto/auth/refresh_token_request";
+import { RefreshTokenResponse } from "@/data/dto/auth/refresh_token_response";
+import { RegisterRequest } from "@/data/dto/auth/register_request";
+import { SendCodeRequest } from "@/data/dto/auth/send_code_request";
+import { User } from "@/data/dto/user/user";
+import type { UserData } from "@/data/services/schemas/user/user";
+
+export class AuthApi {
+  /**
+   * 发送验证码
+   */
+  async sendCode(body: SendCodeRequest): Promise<void> {
+    await httpClient<ApiEnvelope<unknown>>(ApiPath.sendCode, {
+      method: "POST",
+      body: body.toJson(),
+    });
+  }
+
+  /**
+   * 邮箱密码登录
+   */
+  async emailLogin(body: LoginRequest): Promise<LoginResponse> {
+    const env = await httpClient<ApiEnvelope<unknown>>(
+      ApiPath.emailLogin,
+      { method: "POST", body: body.toJson() }
+    );
+    return LoginResponse.fromJson(unwrap(env) as Record<string, unknown>);
+  }
+
+  /**
+   * 注册
+   */
+  async register(body: RegisterRequest): Promise<void> {
+    await httpClient<ApiEnvelope<unknown>>(ApiPath.register, {
+      method: "POST",
+      body: body.toJson(),
+    });
+  }
+
+  /**
+   * Apple 登录
+   */
+  async appleLogin(body: AppleLoginRequest): Promise<LoginResponse> {
+    const env = await httpClient<ApiEnvelope<unknown>>(ApiPath.appleLogin, {
+      method: "POST",
+      body: body.toJson(),
+    });
+    return LoginResponse.fromJson(unwrap(env) as Record<string, unknown>);
+  }
+
+  /**
+   * Google 登录
+   */
+  async googleLogin(body: GoogleLoginRequest): Promise<LoginResponse> {
+    const env = await httpClient<ApiEnvelope<unknown>>(ApiPath.googleLogin, {
+      method: "POST",
+      body: body.toJson(),
+    });
+    return LoginResponse.fromJson(unwrap(env) as Record<string, unknown>);
+  }
+
+  /**
+   * Facebook 登录
+   */
+  async facebookLogin(body: FacebookLoginRequest): Promise<LoginResponse> {
+    const env = await httpClient<ApiEnvelope<unknown>>(
+      ApiPath.facebookLogin,
+      { method: "POST", body: body.toJson() }
+    );
+    return LoginResponse.fromJson(unwrap(env) as Record<string, unknown>);
+  }
+
+  /**
+   * Facebook ID 登录（v7.0 新增）
+   */
+  async facebookIdLogin(body: FbIdLoginRequest): Promise<LoginResponse> {
+    const env = await httpClient<ApiEnvelope<unknown>>(
+      ApiPath.facebookIdLogin,
+      { method: "POST", body: body.toJson() }
+    );
+    return LoginResponse.fromJson(unwrap(env) as Record<string, unknown>);
+  }
+
+  /**
+   * 退出登录
+   */
+  async logout(): Promise<LogoutResponse> {
+    const env = await httpClient<ApiEnvelope<unknown>>(ApiPath.logout, {
+      method: "POST",
+    });
+    return LogoutResponse.fromJson(unwrap(env) as Record<string, unknown>);
+  }
+
+  /**
+   * 游客登录
+   */
+  async guestLogin(body: GuestLoginRequest): Promise<GuestLoginResponse> {
+    const env = await httpClient<ApiEnvelope<unknown>>(ApiPath.guestLogin, {
+      method: "POST",
+      body: body.toJson(),
+    });
+    return GuestLoginResponse.fromJson(unwrap(env) as Record<string, unknown>);
+  }
+
+  /**
+   * 刷新 Token
+   */
+  async refreshToken(
+    body: RefreshTokenRequest
+  ): Promise<RefreshTokenResponse> {
+    const env = await httpClient<ApiEnvelope<unknown>>(ApiPath.refresh, {
+      method: "POST",
+      body: body.toJson(),
+    });
+    return RefreshTokenResponse.fromJson(
+      unwrap(env) as Record<string, unknown>
+    );
+  }
+
+  /**
+   * 获取当前用户信息
+   */
+  async getCurrentUser(): Promise<User> {
+    const env = await httpClient<ApiEnvelope<unknown>>(
+      ApiPath.getCurrentUser
+    );
+    return User.fromJson(unwrap(env) as UserData);
+  }
+}
+
+/**
+ * 全局单例
+ */
+export const authApi = new AuthApi();