Initial commit: suixinkan_ios UIKit rewrite project.

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

suixinkan_ios/App/Navigation/AppTab.swift

@@ -0,0 +1,58 @@
+//
+//  AppTab.swift
+//  suixinkan
+//
+//  Created by Codex on 2026/6/18.
+//
+
+import UIKit
+
+/// 主 Tab 实体，描述底部导航中的每一个一级入口。
+enum AppTab: String, CaseIterable, Identifiable, Hashable {
+    case home
+    case orders
+    case statistics
+    case profile
+
+    var id: Self { self }
+
+    var title: String {
+        switch self {
+        case .home:
+            "首页"
+        case .orders:
+            "订单"
+        case .statistics:
+            "数据"
+        case .profile:
+            "我的"
+        }
+    }
+
+    var systemImage: String {
+        switch self {
+        case .home:
+            "house"
+        case .orders:
+            "doc.text"
+        case .statistics:
+            "chart.bar"
+        case .profile:
+            "person"
+        }
+    }
+
+    /// 构建 Tab 根页面 ViewController。
+    func makeRootViewController(services: AppServices) -> UIViewController {
+        switch self {
+        case .home:
+            return HomeViewController()
+        case .orders:
+            return OrdersViewController()
+        case .statistics:
+            return StatisticsViewController()
+        case .profile:
+            return ProfileViewController()
+        }
+    }
+}