fix: resolve WebAssembly assembly loading and JWT authorization policy errors

- Remove duplicate AddAdditionalAssemblies() call that caused 'Assembly already defined' error
- All Blazor components are already in the main TaxBaik.Web assembly
- Add FastEndpoints JWT authorization policy to fix 'Bearer policy not found' error
- Ensure proper authentication middleware configuration

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

src/TaxBaik.Web/Program.cs

@@ -60,6 +60,16 @@ builder.Services.AddFastEndpoints(config =>
 {
     config.Assemblies = new[] { typeof(Program).Assembly };
 });
+// FastEndpoints Authorization Policy
+builder.Services.AddAuthorization(opts =>
+{
+    opts.DefaultPolicy = new Microsoft.AspNetCore.Authorization.AuthorizationPolicyBuilder(JwtBearerDefaults.AuthenticationScheme)
+        .RequireAuthenticatedUser()
+        .Build();
+    opts.AddPolicy("Bearer", new Microsoft.AspNetCore.Authorization.AuthorizationPolicyBuilder(JwtBearerDefaults.AuthenticationScheme)
+        .RequireAuthenticatedUser()
+        .Build());
+});
 builder.Services.AddProblemDetails();
 builder.Services.AddHealthChecks();
 builder.Services.AddRateLimiter(options =>
@@ -417,7 +427,6 @@ app.MapStaticAssets();
 // API는 웹 서버에서만 제공 (클라이언트 프로젝트 분리 불필요)
 app.MapRazorComponents<TaxBaik.Web.Components.Admin.App>()
    .AddInteractiveWebAssemblyRenderMode()
-   .AddAdditionalAssemblies(typeof(TaxBaik.Web.Components.Admin._Imports).Assembly)
    .AllowAnonymous();
 
 // 애플리케이션 시작/종료 로깅