fix: JWT 인증 설정 추가 - Admin 엔드포인트 인증 활성화

- Microsoft.AspNetCore.Authentication.JwtBearer 패키지 추가
- Program.cs: JWT 인증 스키마 설정
- Middleware: app.UseAuthentication() 추가
- Admin 대시보드 접근 시 인증 필요 (401 Unauthorized 반환)

테스트 결과:
✅ 홈페이지 (200 OK)
✅ 블로그 (200 OK)
✅ 문의 폼 (200 OK)
✅ 로그인 페이지 (200 OK)
✅ 관리자 대시보드 (401 - 인증 필요)

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

TaxBaik.Web/Program.cs

@@ -1,8 +1,11 @@
 using System.IO.Compression;
+using System.Text;
 using System.Text.Encodings.Web;
 using System.Text.Unicode;
+using Microsoft.AspNetCore.Authentication.JwtBearer;
 using Microsoft.AspNetCore.Components.Authorization;
 using Microsoft.AspNetCore.ResponseCompression;
+using Microsoft.IdentityModel.Tokens;
 using MudBlazor.Services;
 using TaxBaik.Application;
 using TaxBaik.Infrastructure;
@@ -14,6 +17,26 @@ var builder = WebApplication.CreateBuilder(args);
 builder.Services.AddRazorPages();
 builder.Services.AddRazorComponents().AddInteractiveServerComponents();
 
+// JWT 인증
+var jwtKey = builder.Configuration["Jwt:SecretKey"] ?? throw new InvalidOperationException("Missing JWT SecretKey");
+var key = Encoding.ASCII.GetBytes(jwtKey);
+
+builder.Services.AddAuthentication(opts =>
+{
+    opts.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
+    opts.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
+})
+.AddJwtBearer(opts =>
+{
+    opts.TokenValidationParameters = new TokenValidationParameters
+    {
+        ValidateIssuerSigningKey = true,
+        IssuerSigningKey = new SymmetricSecurityKey(key),
+        ValidateIssuer = false,
+        ValidateAudience = false
+    };
+});
+
 // Blazor 인증
 builder.Services.AddScoped<AuthService>();
 builder.Services.AddScoped<CustomAuthenticationStateProvider>();
@@ -74,6 +97,7 @@ app.UsePathBase("/taxbaik");
 app.UseResponseCompression();
 app.UseStaticFiles();
 app.UseRouting();
+app.UseAuthentication();
 app.UseAuthorization();
 app.UseAntiforgery();
 

TaxBaik.Web/TaxBaik.Web.csproj

@@ -16,6 +16,7 @@
     <PackageReference Include="BCrypt.Net-Next" Version="4.0.3" />
     <PackageReference Include="System.IdentityModel.Tokens.Jwt" Version="8.2.1" />
     <PackageReference Include="Microsoft.IdentityModel.Tokens" Version="8.2.1" />
+    <PackageReference Include="Microsoft.AspNetCore.Authentication.JwtBearer" Version="8.0.0" />
   </ItemGroup>
 
 </Project>