Integrate CYLTabBar center scan button and unify UIKit navigation.

Add CYLTabBarController with a global scan entry, promote MainTabBarController to the window root after login, replace RouterPath-based navigation with AppNavigator, and fix Profile diffable cell reconfiguration crashes.

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

suixinkan_ios/Features/Main/Views/MainScanPlusButton.swift

@@ -0,0 +1,77 @@
+//
+//  MainScanPlusButton.swift
+//  suixinkan
+//
+
+import CYLTabBarController
+import UIKit
+
+@MainActor
+@objcMembers
+/// 主 TabBar 中间扫码核销按钮，基于 CYLTabBarController 的 PlusButton 机制实现。
+final class MainScanPlusButton: CYLPlusButton, CYLPlusButtonSubclassing {
+
+    /// 点击扫码按钮时的回调，由 `MainTabBarController` 注入。
+    static var onScanTap: (() -> Void)?
+
+    /// 构建中间扫码按钮实例，供 CYLTabBarController 注册使用。
+    static func plusButton() -> Any {
+        let button = MainScanPlusButton(type: .custom)
+        button.frame = CGRect(x: 0, y: 0, width: 70, height: 64)
+        button.configureAppearance()
+        button.addTarget(button, action: #selector(handleScanTap), for: .touchUpInside)
+        return button
+    }
+
+    /// 指定扫码按钮在 TabBar 中的视觉槽位（位于订单与数据之间）。
+    static func indexOfPlusButtonInTabBar() -> UInt {
+        2
+    }
+
+    /// 调整扫码按钮垂直位置，使其略微凸出 TabBar 顶部。
+    static func constantOfPlusButtonCenterYOffset(forTabBarHeight tabBarHeight: CGFloat) -> CGFloat {
+        -6
+    }
+
+    /// 配置圆形背景与扫码图标，对齐参考工程 CustomMainTabBarCenterAction。
+    private func configureAppearance() {
+        backgroundColor = .clear
+
+        let circleSize: CGFloat = 58
+        let circleView = UIView()
+        circleView.isUserInteractionEnabled = false
+        circleView.backgroundColor = AppDesign.primary
+        circleView.layer.cornerRadius = circleSize / 2
+        addSubview(circleView)
+
+        let symbolConfig = UIImage.SymbolConfiguration(pointSize: 30, weight: .bold)
+        let iconView = UIImageView(
+            image: UIImage(systemName: "qrcode.viewfinder", withConfiguration: symbolConfig)
+        )
+        iconView.tintColor = .white
+        iconView.contentMode = .scaleAspectFit
+        iconView.isUserInteractionEnabled = false
+        addSubview(iconView)
+
+        circleView.translatesAutoresizingMaskIntoConstraints = false
+        iconView.translatesAutoresizingMaskIntoConstraints = false
+        NSLayoutConstraint.activate([
+            circleView.centerXAnchor.constraint(equalTo: centerXAnchor),
+            circleView.centerYAnchor.constraint(equalTo: centerYAnchor),
+            circleView.widthAnchor.constraint(equalToConstant: circleSize),
+            circleView.heightAnchor.constraint(equalToConstant: circleSize),
+            iconView.centerXAnchor.constraint(equalTo: circleView.centerXAnchor),
+            iconView.centerYAnchor.constraint(equalTo: circleView.centerYAnchor),
+            iconView.widthAnchor.constraint(equalToConstant: 30),
+            iconView.heightAnchor.constraint(equalToConstant: 30)
+        ])
+
+        accessibilityLabel = "扫码核销"
+        accessibilityIdentifier = "main.scan"
+    }
+
+    /// 响应用户点击，触发全局扫码流程。
+    @objc private func handleScanTap() {
+        Self.onScanTap?()
+    }
+}