Add bumper variant management: implement API endpoints for adding, updating, and removing bumper text variants, enhance data models to support variant details, and update scheduling logic to utilize variants. Refactor related components for improved bumper template handling and ensure proper error management for variant operations.

backend/src/TeleWave.Application/Broadcast/Bumpers/UpdateBumperTextVariantCommand.cs

@@ -0,0 +1,19 @@
+using LiteCqrs;
+using TeleWave.Application.Common.Models;
+using TeleWave.Domain.Broadcast;
+
+namespace TeleWave.Application.Broadcast.Bumpers;
+
+/// <summary>Обновить подблок: имя, режим текста, текст и правило показа.</summary>
+public sealed record UpdateBumperTextVariantCommand(
+    Guid ChannelId,
+    Guid TemplateId,
+    Guid VariantId,
+    string Name,
+    BumperTextKind Kind,
+    string NowLabel,
+    string NextLabel,
+    string Line1,
+    string Line2,
+    BumperTrigger Trigger
+) : ICommand<Result>;