Replace CYLTabBarController with native UITabBarController for main tabs.

Use a system scan tab slot with MainScanTabItem interception so scanner presentation no longer depends on CYL PlusButton, and remove the CYLTabBarController pod dependency.

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

suixinkan_ios/Features/Main/Views/MainScanTabItem.swift

@@ -0,0 +1,21 @@
+//
+//  MainScanTabItem.swift
+//  suixinkan
+//
+
+import UIKit
+
+@MainActor
+/// 主 TabBar 中间扫码核销入口，负责构建系统 TabBarItem。
+enum MainScanTabItem {
+
+    /// 构建系统扫码 TabBarItem，点击行为由 `MainTabBarController` 拦截处理。
+    static func makeTabBarItem() -> UITabBarItem {
+        let image = UIImage(named: "icon_scan")?.withRenderingMode(.alwaysOriginal)
+        let selectedImage = UIImage(named: "icon_scan")?.withRenderingMode(.alwaysOriginal)
+        let item = UITabBarItem(title: "扫码", image: image, selectedImage: selectedImage)
+        item.accessibilityLabel = "扫码核销"
+        item.accessibilityIdentifier = "main.scan"
+        return item
+    }
+}