Add TV bumpers functionality: introduce configuration options for bumpers in .env.example and appsettings.json, enhance ChannelEndpoints to manage jingles and bumper assets, and update Channel and ScheduleEntry models to support bumper logic. Implement validation for bumper settings and integrate bumper handling in scheduling logic.

backend/src/TeleWave.Application/Media/ListMedia/ListMediaAssetsQueryHandler.cs

@@ -2,6 +2,7 @@ using LiteCqrs;
 using Microsoft.EntityFrameworkCore;
 using TeleWave.Application.Common.Interfaces;
 using TeleWave.Application.Common.Models;
+using TeleWave.Domain.Media;
 
 namespace TeleWave.Application.Media.ListMedia;
 
@@ -13,7 +14,9 @@ public sealed class ListMediaAssetsQueryHandler(IAppDbContext dbContext)
         CancellationToken cancellationToken
     )
     {
-        var q = dbContext.MediaAssets.AsNoTracking();
+        // Сгенерированные системой ассеты (ТВ-заставки) не показываем в библиотеке медиа.
+        var q = dbContext.MediaAssets.AsNoTracking()
+            .Where(x => x.Source != MediaSource.Generated);
 
         if (query.Statuses.Count > 0)
             q = q.Where(x => query.Statuses.Contains(x.Status));