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/UI/Common/AppCardView.swift

@@ -0,0 +1,44 @@
+//
+//  AppCardView.swift
+//  suixinkan
+//
+
+import SnapKit
+import UIKit
+
+/// 标准白底卡片容器，统一圆角与可选描边。
+final class AppCardView: UIView {
+
+    /// 卡片内容区，子视图应添加到此 container。
+    let contentView = UIView()
+
+    private let showsBorder: Bool
+
+    /// - Parameter showsBorder: 是否显示 1px 描边（默认 false，flat 风格）。
+    init(showsBorder: Bool = false) {
+        self.showsBorder = showsBorder
+        super.init(frame: .zero)
+        setupUI()
+    }
+
+    @available(*, unavailable)
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+
+    private func setupUI() {
+        backgroundColor = AppColor.cardBackground
+        layer.cornerRadius = AppRadius.md
+        clipsToBounds = true
+
+        if showsBorder {
+            layer.borderWidth = 1
+            layer.borderColor = AppColor.cardOutline.cgColor
+        }
+
+        addSubview(contentView)
+        contentView.snp.makeConstraints { make in
+            make.edges.equalToSuperview()
+        }
+    }
+}