修复 Tab 导航栈路径绑定，确保子页面 push 后立即响应。

直接观察 RouterPath 并绑定 NavigationStack，移除未使用的 AppTab/AppRouter 辅助 API。

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

suixinkan/Features/Main/Views/MainTabsView.swift

@@ -141,7 +141,17 @@ private struct TabNavigationStackHost: View {
     let tab: AppTab
 
     var body: some View {
-        NavigationStack(path: appRouter.binding(for: tab)) {
+        TabNavigationStackContent(tab: tab, router: appRouter.router(for: tab))
+    }
+}
+
+/// 直接观察单个 Tab 的路由路径，确保子页面修改 RouterPath 后导航栈能立即响应。
+private struct TabNavigationStackContent: View {
+    let tab: AppTab
+    @ObservedObject var router: RouterPath
+
+    var body: some View {
+        NavigationStack(path: $router.path) {
             tab.rootView
                 .navigationTitle(tab.title)
                 .navigationDestination(for: AppRoute.self) { route in
@@ -149,7 +159,7 @@ private struct TabNavigationStackHost: View {
                         .toolbar(route.hidesTabBarWhenPushed ? .hidden : .visible, for: .tabBar)
                 }
         }
-        .environmentObject(appRouter.router(for: tab))
+        .environmentObject(router)
     }
 }