Day 1 · Step 1 — Create up-api

dotnet new webapi -n up-api

Default template only — no packages, no dotnet run. Verify/add to Program.cs:

builder.Services.AddControllers();
builder.Services.AddCors(options =>
{
    options.AddDefaultPolicy(policy =>
    {
        policy.AllowAnyOrigin()
              .AllowAnyMethod()
              .AllowAnyHeader();
    });
});