feat: 对齐常驻商城与七鱼客服交互

- 同步商城 H5 登录态与原生 token
- 完善商城/原生 tab 切换、动画及返回交互
- 修复七鱼客服键盘避让和状态栏恢复
- 调整开屏跳过按钮与登录入口交互

lib/features/web/application/mall_web_host_controller.dart

@@ -1,30 +1,121 @@
 import 'package:flutter/foundation.dart';
 
 class MallWebHostState {
-  const MallWebHostState({this.url, this.visible = false});
+  const MallWebHostState({
+    this.url,
+    this.visible = false,
+    this.isShowingQiyuPage = false,
+    this.isQiyuKeyboardActive = false,
+  });
+
   final String? url;
   final bool visible;
+  final bool isShowingQiyuPage;
+  final bool isQiyuKeyboardActive;
 }
 
-/// 进程常驻的商城 WebView 状态，切换原生 Tab 时不销毁商城页面。
+/// Process-lifetime presentation state for the resident mall WebView.
 class MallWebHostController {
   MallWebHostController._();
-  static final instance = MallWebHostController._();
-  final state = ValueNotifier(const MallWebHostState());
-  Future<void> Function()? _backHandler;
 
-  void preload(String url) {
-    final old = state.value;
-    if (old.url == url) return;
-    state.value = MallWebHostState(url: url, visible: old.visible);
+  static final instance = MallWebHostController._();
+
+  final state = ValueNotifier(const MallWebHostState());
+  String? _pendingPreloadUrl;
+  Future<void> Function()? _clearCache;
+  Future<void> Function()? _handleSystemBack;
+
+  void open(Uri url) {
+    _pendingPreloadUrl = null;
+    state.value = MallWebHostState(url: url.toString(), visible: true);
   }
 
-  void open(String url) =>
-      state.value = MallWebHostState(url: url, visible: true);
-  void dismiss() => state.value = MallWebHostState(url: state.value.url);
-  void clear() => state.value = const MallWebHostState();
-  void attachBackHandler(Future<void> Function() handler) =>
-      _backHandler = handler;
-  void detachBackHandler() => _backHandler = null;
-  Future<void> handleBack() => _backHandler?.call() ?? Future.value();
+  void preload(Uri url) {
+    final current = state.value;
+    if (current.visible) {
+      if (current.url == null ||
+          cacheKeyFor(current.url!) != cacheKeyFor(url.toString())) {
+        _pendingPreloadUrl = url.toString();
+      }
+      return;
+    }
+    if (current.url != null &&
+        cacheKeyFor(current.url!) == cacheKeyFor(url.toString())) {
+      return;
+    }
+    state.value = MallWebHostState(
+      url: url.toString(),
+      visible: current.visible,
+    );
+  }
+
+  void dismiss() {
+    final current = state.value;
+    final pending = _pendingPreloadUrl;
+    _pendingPreloadUrl = null;
+    state.value = MallWebHostState(url: pending ?? current.url);
+  }
+
+  void setShowingQiyuPage(bool isShowingQiyuPage) {
+    final current = state.value;
+    if (current.isShowingQiyuPage == isShowingQiyuPage) return;
+    state.value = MallWebHostState(
+      url: current.url,
+      visible: current.visible,
+      isShowingQiyuPage: isShowingQiyuPage,
+      isQiyuKeyboardActive: isShowingQiyuPage
+          ? current.isQiyuKeyboardActive
+          : false,
+    );
+  }
+
+  void setQiyuKeyboardActive(bool active) {
+    final current = state.value;
+    if (current.isQiyuKeyboardActive == active) return;
+    state.value = MallWebHostState(
+      url: current.url,
+      visible: current.visible,
+      isShowingQiyuPage: current.isShowingQiyuPage,
+      isQiyuKeyboardActive: active,
+    );
+  }
+
+  void attachCacheClearer(Future<void> Function() clearer) =>
+      _clearCache = clearer;
+
+  void detachCacheClearer() => _clearCache = null;
+
+  Future<void> clear() async {
+    await _clearCache?.call();
+    _pendingPreloadUrl = null;
+    state.value = const MallWebHostState();
+  }
+
+  static Uri uriForTheme(Uri uri, {required bool isDark}) {
+    final query = Map<String, List<String>>.from(uri.queryParametersAll);
+    query['isNight'] = [isDark ? '1' : '0'];
+    return uri.replace(queryParameters: query);
+  }
+
+  void attachSystemBackHandler(Future<void> Function() handler) {
+    _handleSystemBack = handler;
+  }
+
+  void detachSystemBackHandler() => _handleSystemBack = null;
+
+  Future<void> handleSystemBack() =>
+      _handleSystemBack?.call() ?? Future<void>.value();
+
+  static String cacheKeyFor(String rawUrl) {
+    final uri = Uri.tryParse(rawUrl);
+    if (uri == null) return rawUrl;
+    return uri
+        .replace(
+          queryParameters: uri.queryParameters['isNight'] == null
+              ? const <String, String>{}
+              : <String, String>{'isNight': uri.queryParameters['isNight']!},
+          fragment: '',
+        )
+        .toString();
+  }
 }