Set up ASP.NET Core Web API project structure

Initialized the ASP.NET Core application in `Program.cs` with
services for controllers, Swagger/OpenAPI, and middleware
for HTTPS redirection and authorization.

Added `launchSettings.json` to configure application launch
profiles for HTTP, HTTPS, and IIS Express environments.

Updated `ReC.API.csproj` to target .NET 8.0, enable nullable
reference types, and include the `Swashbuckle.AspNetCore`
package for Swagger support.

Added `appsettings.json` and `appsettings.Development.json`
for logging and environment-specific configurations.

Reorganized the solution structure in `ReC.sln` by moving
the `ReC.API` project under a `src` folder and updating
the `NestedProjects` section.

src/ReC.API/Program.cs

@@ -0,0 +1,25 @@
+var builder = WebApplication.CreateBuilder(args);
+
+// Add services to the container.
+
+builder.Services.AddControllers();
+// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
+builder.Services.AddEndpointsApiExplorer();
+builder.Services.AddSwaggerGen();
+
+var app = builder.Build();
+
+// Configure the HTTP request pipeline.
+if (app.Environment.IsDevelopment())
+{
+    app.UseSwagger();
+    app.UseSwaggerUI();
+}
+
+app.UseHttpsRedirection();
+
+app.UseAuthorization();
+
+app.MapControllers();
+
+app.Run();