feat: 更新 WebView 数据目录，添加持久存储清理逻辑；优化 URL 生成和 H5 路由刷新时的品牌保持

lib/config/app_config.dart

@@ -21,33 +21,14 @@ class AppConfig {
     final host = environmentHosts.isNotEmpty
         ? environmentHosts.first
         : 'h5-im.imharry.work';
-    return _withShellBranding(
+    return withFreshShellParams(
       _normalizeHomeUrl(host),
       appName: appName,
       appLogo: appLogo,
     );
   }
 
-  static String withFreshShellCacheBust(String url) {
-    final uri = Uri.parse(url);
-    final queryParameters = Map<String, String>.from(uri.queryParameters)
-      ..['shell_cache_bust'] = DateTime.now().millisecondsSinceEpoch.toString();
-
-    return uri.replace(queryParameters: queryParameters).toString();
-  }
-
-  static String _normalizeHomeUrl(String host) {
-    final value = host.trim();
-    final normalized =
-        value.startsWith('http://') || value.startsWith('https://')
-            ? value
-            : 'https://$value';
-    final uri = Uri.parse(normalized);
-    final path = uri.path.isEmpty ? '/' : uri.path;
-    return uri.replace(path: path).toString();
-  }
-
-  static String _withShellBranding(
+  static String withFreshShellParams(
     String url, {
     String? appName,
     String? appLogo,
@@ -77,4 +58,23 @@ class AppConfig {
         )
         .toString();
   }
+
+  static String withFreshShellCacheBust(String url) {
+    final uri = Uri.parse(url);
+    final queryParameters = Map<String, String>.from(uri.queryParameters)
+      ..['shell_cache_bust'] = DateTime.now().millisecondsSinceEpoch.toString();
+
+    return uri.replace(queryParameters: queryParameters).toString();
+  }
+
+  static String _normalizeHomeUrl(String host) {
+    final value = host.trim();
+    final normalized =
+        value.startsWith('http://') || value.startsWith('https://')
+            ? value
+            : 'https://$value';
+    final uri = Uri.parse(normalized);
+    final path = uri.path.isEmpty ? '/' : uri.path;
+    return uri.replace(path: path).toString();
+  }
 }