fix: ApiClient 의존성 주입 등록 및 using 추가

Program.cs:
- using QuantEngine.Web.Services 추가
- builder.Services.AddHttpClient<ApiClient>();
- builder.Services.AddScoped<ApiClient>();

Collection.razor에서 ApiClient 주입 가능하도록 함

src/dotnet/QuantEngine.Web/Program.cs

@@ -1,4 +1,5 @@
 using QuantEngine.Web.Components;
+using QuantEngine.Web.Services;
 using QuantEngine.Infrastructure.Data;
 using QuantEngine.Infrastructure.Repositories;
 using QuantEngine.Infrastructure.Services;
@@ -41,7 +42,9 @@ builder.Services.AddScoped<ICollectionRepository, CollectionRepository>();
 builder.Services.AddScoped<ITokenCache, PostgresTokenCache>();
 builder.Services.AddScoped<IKisApiClient, KisApiClient>();
 
-builder.Services.AddHttpClient();
+// HTTP Client & API Services
+builder.Services.AddHttpClient<ApiClient>();
+builder.Services.AddScoped<ApiClient>();
 
 var app = builder.Build();