YARP app to replace `nginx` bits in JS example

Does YARP support a simple proxy config, where I can intercept /api HTTP requests, and redirect them to the configured weather API url?

Yes: https://microsoft.github.io/reverse-proxy/articles/config-files.html

Perhaps we could add a YARP project to the solution and use it as the host for all the JS apps. In theory, the YARP project can be as simple as:

var builder = WebApplication.CreateBuilder(args);
builder.Services.AddReverseProxy()
    .LoadFromConfig(builder.Configuration.GetSection("ReverseProxy"));
var app = builder.Build();
app.MapReverseProxy();
app.Run();

Originally posted by @DamianEdwards in https://github.com/dotnet/aspire-samples/pull/226#discussion_r1578216683

Start by locating the JavaScript example's nginx configuration and the solution entry points; review the referenced YARP configuration and getting-started documentation alongside the provided C# setup. Done means the JavaScript apps are hosted through a YARP project and /api requests reach the configured weather API without the nginx pieces.