void.cat/VoidCat/Program.cs

using VoidCat;

var builder = WebApplication.CreateBuilder(args);

var services = builder.Services;
services.AddRouting();
services.AddControllers();

var configuration = builder.Configuration;
var voidSettings = configuration.GetSection("Settings").Get<VoidSettings>();
services.AddSingleton(voidSettings);

var app = builder.Build();

app.UseStaticFiles();
app.UseRouting();
app.UseEndpoints(ep =>
{
    ep.MapControllers();
    ep.MapFallbackToFile("index.html");
});

app.Run();