Add broadcast scheduling features: implement Show and Channel entities, enhance AppDbContext and DependencyInjection for broadcasting, and update API routing. Include migration for new database schema and update documentation for broadcast-related functionalities.

backend/src/TeleWave.Application/Library/CreateShow/CreateShowCommand.cs

@@ -0,0 +1,8 @@
+using LiteCqrs;
+using TeleWave.Application.Common.Models;
+using TeleWave.Domain.Library;
+
+namespace TeleWave.Application.Library.CreateShow;
+
+public sealed record CreateShowCommand(string Name, ShowKind Kind, string? Description)
+    : ICommand<Result<Guid>>;