Introduce unified design tokens and migrate Home, Orders, and Statistics UI.

Establish AppColor/AppFont/AppSpacing/AppRadius theming, shared components, and design-system docs so pilot screens align with Android while keeping iOS-native spacing and touch targets.

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

suixinkan/Theme/AppNavigationBarAppearance.swift

@@ -0,0 +1,28 @@
+//
+//  AppNavigationBarAppearance.swift
+//  suixinkan
+//
+
+import UIKit
+
+/// 全局 UINavigationBar 外观配置。
+enum AppNavigationBarAppearance {
+
+    /// 应用标准导航栏样式（白底、无 shadow、主色标题）。
+    static func applyGlobalAppearance() {
+        let appearance = UINavigationBarAppearance()
+        appearance.configureWithOpaqueBackground()
+        appearance.backgroundColor = AppColor.cardBackground
+        appearance.shadowColor = .clear
+        appearance.titleTextAttributes = [
+            .foregroundColor: AppColor.textPrimary,
+            .font: UIFont.app(.title),
+        ]
+
+        let navigationBar = UINavigationBar.appearance()
+        navigationBar.standardAppearance = appearance
+        navigationBar.scrollEdgeAppearance = appearance
+        navigationBar.compactAppearance = appearance
+        navigationBar.tintColor = AppColor.primary
+    }
+}