Implement background clip functionality for bumpers

Enhanced the bumper system to support a new background type, 'Clip', allowing text to be overlaid on existing video clips. This update includes the addition of a BackgroundClipShowId property in various records and classes, ensuring that the clip's duration dictates the bumper length. Updated validation rules, mapping, and rendering logic to accommodate this new feature. Localization strings were also updated to reflect the new background option and its implications for audio handling.

backend/tests/TeleWave.Application.Tests/Broadcast/BumperPreviewTests.cs

@@ -26,13 +26,15 @@ public class BumperPreviewTests
         AppDbContext db,
         IBumperRenderer? renderer = null,
         IBumperTemplateStorage? storage = null,
-        IImageStore? imageStore = null
+        IImageStore? imageStore = null,
+        IMediaStorage? mediaStorage = null
     ) =>
         new(
             db,
             renderer ?? Substitute.For<IBumperRenderer>(),
             storage ?? Substitute.For<IBumperTemplateStorage>(),
             imageStore ?? Substitute.For<IImageStore>(),
+            mediaStorage ?? Substitute.For<IMediaStorage>(),
             Options.Create(new BumperOptions()),
             Options.Create(new StreamingOptions { SegmentSeconds = 5 })
         );

backend/tests/TeleWave.Application.Tests/Broadcast/BumperSpecLoaderTests.cs

@@ -27,12 +27,14 @@ public class BumperSpecLoaderTests
     private static BumperSpecLoader NewLoader(
         Infrastructure.Persistence.AppDbContext db,
         IBumperTemplateStorage? storage = null,
-        IImageStore? images = null
+        IImageStore? images = null,
+        IMediaStorage? media = null
     ) =>
         new(
             db,
             storage ?? Substitute.For<IBumperTemplateStorage>(),
             images ?? Substitute.For<IImageStore>(),
+            media ?? Substitute.For<IMediaStorage>(),
             Options.Create(new BumperOptions()),
             Options.Create(new StreamingOptions { SegmentSeconds = 5 })
         );