feat: wip on login endpoint

- added basic REPR pattern
- added basic vert architecture
- implemented basica validation for single test case

src/FiscalOS.API/Login/Endpoint.cs

@@ -0,0 +1,18 @@
+namespace FiscalOS.API.Login;
+
+internal static class Endpoint
+{
+  private const string Route = "/login";
+
+  public static RouteHandlerBuilder MapLoginEndpoint(this WebApplication app)
+  {
+    return app.MapPost(Route, HandleAsync);
+  }
+
+  private static async Task<IResult> HandleAsync([FromBody] LoginRequest loginRequest)
+  {
+    Console.WriteLine(loginRequest.Username);
+    Console.WriteLine(loginRequest.Password);
+    return Results.Ok();
+  }
+}