Refactor bumper template background management: rename background upload endpoint to reflect new functionality, update related command and handler to use image ID instead of extension, and adjust data models to support image references. Remove obsolete background handling code and enhance UI components for improved image selection and display.

backend/src/TeleWave.Api/Endpoints/ChannelEndpoints.cs

@@ -75,7 +75,7 @@ public static class ChannelEndpoints
             .MapDelete("/{id:guid}/bumper/templates/{templateId:guid}/audio", ClearTemplateAudio)
             .Produces(StatusCodes.Status204NoContent);
         admin
-            .MapPut("/{id:guid}/bumper/templates/{templateId:guid}/background", UploadTemplateBackground)
+            .MapPut("/{id:guid}/bumper/templates/{templateId:guid}/background", SetTemplateBackground)
             .Produces(StatusCodes.Status204NoContent);
         admin
             .MapDelete("/{id:guid}/bumper/templates/{templateId:guid}/background", ClearTemplateBackground)
@@ -333,27 +333,18 @@ public static class ChannelEndpoints
         return result.ToHttpResult();
     }
 
-    private static async Task<IResult> UploadTemplateBackground(
+    private static async Task<IResult> SetTemplateBackground(
         Guid id,
         Guid templateId,
-        string fileName,
-        HttpRequest request,
-        IBumperTemplateStorage storage,
+        SetBumperTemplateBackgroundBody body,
         ISender sender,
         CancellationToken cancellationToken
     )
     {
-        if (ResolveBumperExtension(fileName, request, BumperFiles.BackgroundExtensions) is not { } ext)
-            return ChannelErrors.InvalidBumperFile.ToProblem();
-
-        await storage.SaveBackgroundAsync(templateId, ext, request.Body, cancellationToken);
-
         var result = await sender.Send(
-            new SetBumperTemplateBackgroundCommand(id, templateId, ext),
+            new SetBumperTemplateBackgroundCommand(id, templateId, body.ImageId),
             cancellationToken
         );
-        if (!result.IsSuccess)
-            storage.DeleteBackground(templateId);
         return result.ToHttpResult();
     }
 
@@ -539,6 +530,8 @@ public sealed record AddChannelAdBody(Guid MediaAssetId);
 
 public sealed record AddBumperTemplateBody(string Name);
 
+public sealed record SetBumperTemplateBackgroundBody(Guid ImageId);
+
 public sealed record UpdateBumperTemplateBody(
     string Name,
     string BackgroundColor,
@@ -547,24 +540,11 @@ public sealed record UpdateBumperTemplateBody(
     string TextColor
 );
 
-/// <summary>Ограничения на загружаемые файлы блока заставки (звук/фон-картинка).</summary>
+/// <summary>Ограничения на загружаемый звук блока заставки (фон-картинка — через общий реестр).</summary>
 internal static class BumperFiles
 {
     public const long MaxBytes = 200L * 1024 * 1024; // 200 МБ
 
-    // Фон блока — только картинка (видео-фоны в новой модели не поддерживаются).
-    public static readonly IReadOnlySet<string> BackgroundExtensions = new HashSet<string>(
-        StringComparer.OrdinalIgnoreCase
-    )
-    {
-        ".jpg",
-        ".jpeg",
-        ".png",
-        ".webp",
-        ".bmp",
-        ".gif",
-    };
-
     public static readonly IReadOnlySet<string> AudioExtensions = new HashSet<string>(
         StringComparer.OrdinalIgnoreCase
     )