同步 Android 启动页到 iOS，并在冷启动期间静默恢复登录态。

新增 SplashView、SplashCoordinator 与 Launch Screen 资源，移除冷启动 Lottie；LoginView 加载 App 配置。同时将 token 存储迁移至 UserDefaults，并更新相关测试与文档。

Co-authored-by: Cursor <cursoragent@cursor.com>

suixinkan/Features/Auth/Views/LoginView.swift

@@ -14,6 +14,7 @@ struct LoginView: View {
     @EnvironmentObject private var permissionContext: PermissionContext
     @EnvironmentObject private var toastCenter: ToastCenter
     @Environment(\.authAPI) private var authAPI
+    @Environment(\.appConfigAPI) private var appConfigAPI
     @Environment(\.profileAPI) private var profileAPI
     @Environment(\.accountContextAPI) private var accountContextAPI
     @Environment(\.authSessionCoordinator) private var authSessionCoordinator
@@ -85,6 +86,7 @@ struct LoginView: View {
         }
         .task {
             viewModel.applyPreferences(authSessionCoordinator.loginPreferences())
+            await viewModel.loadAppConfig(appConfigAPI: appConfigAPI)
         }
     }