Update scheduling parameters and refactor channel endpoints: extend HorizonDays to 7 and RetentionDays to 90 in appsettings.json. Consolidate channel-related endpoint logic by removing obsolete files and enhancing the ShowEndpoints with audience and genre management capabilities. Improve error handling and streamline command handlers for channel operations.

backend/src/TeleWave.Application/Programming/Groups/DeleteGroup/DeleteGroupCommandHandler.cs

@@ -0,0 +1,24 @@
+using LiteCqrs;
+using Microsoft.EntityFrameworkCore;
+using TeleWave.Application.Common.Interfaces;
+using TeleWave.Application.Common.Models;
+
+namespace TeleWave.Application.Programming.Groups.DeleteGroup;
+
+public sealed class DeleteGroupCommandHandler(IAppDbContext dbContext)
+    : ICommandHandler<DeleteGroupCommand, Result>
+{
+    public async Task<Result> Handle(DeleteGroupCommand command, CancellationToken cancellationToken)
+    {
+        var group = await dbContext.Groups.FirstOrDefaultAsync(
+            g => g.Id == command.GroupId,
+            cancellationToken
+        );
+        if (group is null)
+            return Result.Failure(GroupErrors.NotFound);
+
+        // TODO(срез 1C): запретить удаление, пока на группу ссылается слот сетки.
+        dbContext.Groups.Remove(group);
+        return Result.Success();
+    }
+}