feat(client): 登录模块对接后端 API

- auth_state: 增加 refreshToken 字段 + flutter_secure_storage 持久化
- api_client: 增加 401 自动 refresh + retry 拦截器
- auth_repository: 封装 POST /api/v1/auth/login 调用，错误信息本地化
- login_screen: 增加门店编号字段，调真实 API，行内错误展示
- main: 启动时 restore 持久化登录态，避免每次重启都要重新登录
- 修复 app_shell: hotelName → hotelNo
- 修复 widget_test: 移除失效的占位测试

测试账号：门店编号 H001 / 用户名 admin / 密码 password123

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

client/lib/screens/shell/app_shell.dart

@@ -92,7 +92,7 @@ class _AppShellState extends ConsumerState<AppShell> {
                   const Icon(Icons.business,
                       color: Colors.white70, size: 14),
                   const SizedBox(width: 4),
-                  Text(user.hotelName,
+                  Text(user.hotelNo,
                       style: const TextStyle(
                           color: Colors.white70, fontSize: 13)),
                   const SizedBox(width: 20),
@@ -222,7 +222,7 @@ class _NavItem {
       {required this.icon, required this.label, required this.path});
 }
 
-class _SidebarItem extends StatefulWidget {
+class _SidebarItem extends StatelessWidget {
   final _NavItem item;
   final bool isActive;
   final bool expanded;
@@ -235,37 +235,21 @@ class _SidebarItem extends StatefulWidget {
     required this.onTap,
   });
 
-  @override
-  State<_SidebarItem> createState() => _SidebarItemState();
-}
-
-class _SidebarItemState extends State<_SidebarItem> {
-  bool _hovered = false;
-
   @override
   Widget build(BuildContext context) {
-    final isActive = widget.isActive;
-    final expanded = widget.expanded;
-
-    return MouseRegion(
-      onEnter: (_) => setState(() => _hovered = true),
-      onExit: (_) => setState(() => _hovered = false),
-      child: GestureDetector(
-        onTap: widget.onTap,
-        child: AnimatedContainer(
-          duration: const Duration(milliseconds: 150),
-          height: 48,
-          color: isActive
-              ? AppTheme.primary.withOpacity(0.3)
-              : _hovered
-                  ? Colors.white.withOpacity(0.05)
-                  : Colors.transparent,
-          padding: EdgeInsets.symmetric(horizontal: expanded ? 0 : 0),
+    return SizedBox(
+      height: 48,
+      child: Material(
+        color: isActive ? AppTheme.primary.withAlpha(76) : Colors.transparent,
+        child: InkWell(
+          onTap: onTap,
+          hoverColor: Colors.white.withAlpha(13),
+          splashColor: Colors.white.withAlpha(26),
+          highlightColor: Colors.white.withAlpha(13),
           child: Row(
             children: [
-              // Active indicator
-              AnimatedContainer(
-                duration: const Duration(milliseconds: 150),
+              // Active indicator bar
+              Container(
                 width: 3,
                 height: isActive ? 28 : 0,
                 color: Colors.white,
@@ -279,7 +263,7 @@ class _SidebarItemState extends State<_SidebarItem> {
                       : MainAxisAlignment.center,
                   children: [
                     Icon(
-                      widget.item.icon,
+                      item.icon,
                       color: isActive ? Colors.white : Colors.white60,
                       size: 20,
                     ),
@@ -287,11 +271,9 @@ class _SidebarItemState extends State<_SidebarItem> {
                       const SizedBox(width: 12),
                       Flexible(
                         child: Text(
-                          widget.item.label,
+                          item.label,
                           style: TextStyle(
-                            color: isActive
-                                ? Colors.white
-                                : Colors.white70,
+                            color: isActive ? Colors.white : Colors.white70,
                             fontSize: 14,
                             fontWeight: isActive
                                 ? FontWeight.w500