Implement asynchronous bumper rendering and add integration tests: refactor BumperAsset to support async rendering, introduce BumperRenderBackgroundService for processing, and create TeleWave.Integration.Tests with Testcontainers-Postgres for comprehensive testing of scheduling and bumper generation scenarios. Update documentation and ensure tests skip if Docker is not available.

backend/src/TeleWave.Infrastructure/Media/BumperRenderQueue.cs

@@ -0,0 +1,20 @@
+using System.Threading.Channels;
+using TeleWave.Application.Common.Interfaces;
+
+namespace TeleWave.Infrastructure.Media;
+
+/// <summary>Сигнальная очередь-будильник поверх Channel (id ассета — лишь сигнал; работу берём из БД).</summary>
+public sealed class BumperRenderQueue : IBumperRenderQueue
+{
+    private readonly Channel<Guid> _channel = Channel.CreateUnbounded<Guid>(
+        new UnboundedChannelOptions { SingleReader = true }
+    );
+
+    public void Enqueue(Guid assetId) => _channel.Writer.TryWrite(assetId);
+
+    public async ValueTask WaitAsync(CancellationToken cancellationToken)
+    {
+        await _channel.Reader.ReadAsync(cancellationToken);
+        while (_channel.Reader.TryRead(out _)) { }
+    }
+}