feat: NavMenu 로그아웃 버튼 + 토큰 갱신 로직

1. NavMenu에 사용자명 표시 및 로그아웃 버튼 추가
2. CustomAuthenticationStateProvider에 토큰 만료 검증 추가
3. Routes.razor 간소화 (AuthorizeRouteView 사용)
4. 미인증 사용자는 _Imports.razor의 [Authorize]로 보호됨

테스트 계정: admin / admin123

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

TaxBaik.Admin/Shared/NavMenu.razor

@@ -1,6 +1,26 @@
-<div class="top-row ps-3 navbar navbar-dark">
+@using System.Security.Claims
+@using Microsoft.AspNetCore.Components.Authorization
+@using TaxBaik.Admin.Services
+@inject AuthenticationStateProvider AuthStateProvider
+@inject CustomAuthenticationStateProvider CustomAuthStateProvider
+@inject NavigationManager NavigationManager
+
+<div class="top-row ps-3 navbar navbar-dark">
     <div class="container-fluid">
         <a class="navbar-brand" href="">TaxBaik.Admin</a>
+        <div class="d-flex align-items-center gap-3 ms-auto">
+            <AuthorizeView>
+                <Authorized>
+                    <div class="user-info text-light">
+                        <span>@context.User.FindFirst(ClaimTypes.Name)?.Value</span>
+                        <button class="btn btn-sm btn-outline-light ms-2" @onclick="HandleLogout">로그아웃</button>
+                    </div>
+                </Authorized>
+                <NotAuthorized>
+                    <a href="login" class="btn btn-sm btn-outline-light">로그인</a>
+                </NotAuthorized>
+            </AuthorizeView>
+        </div>
         <button title="Navigation menu" class="navbar-toggler" @onclick="ToggleNavMenu">
             <span class="navbar-toggler-icon"></span>
         </button>
@@ -10,18 +30,18 @@
 <div class="@NavMenuCssClass nav-scrollable" @onclick="ToggleNavMenu">
     <nav class="flex-column">
         <div class="nav-item px-3">
-            <NavLink class="nav-link" href="" Match="NavLinkMatch.All">
-                <span class="oi oi-home" aria-hidden="true"></span> Home
+            <NavLink class="nav-link" href="dashboard" Match="NavLinkMatch.All">
+                <span class="oi oi-home" aria-hidden="true"></span> 대시보드
             </NavLink>
         </div>
         <div class="nav-item px-3">
-            <NavLink class="nav-link" href="counter">
-                <span class="oi oi-plus" aria-hidden="true"></span> Counter
+            <NavLink class="nav-link" href="blog">
+                <span class="oi oi-document" aria-hidden="true"></span> 블로그
             </NavLink>
         </div>
         <div class="nav-item px-3">
-            <NavLink class="nav-link" href="fetchdata">
-                <span class="oi oi-list-rich" aria-hidden="true"></span> Fetch data
+            <NavLink class="nav-link" href="inquiries">
+                <span class="oi oi-envelope-closed" aria-hidden="true"></span> 문의사항
             </NavLink>
         </div>
     </nav>
@@ -36,4 +56,10 @@
     {
         collapseNavMenu = !collapseNavMenu;
     }
+
+    private async Task HandleLogout()
+    {
+        await CustomAuthStateProvider.LogoutAsync();
+        NavigationManager.NavigateTo("/login", forceLoad: true);
+    }
 }