Add interstitial endpoints and enhance media and template functionalities: implement MapInterstitialEndpoints in Program.cs, add preview functionality for media assets in MediaEndpoints, and introduce template preview capabilities in TemplateEndpoints. Remove obsolete bumper settings from Channel and related classes to streamline configuration.

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

@@ -0,0 +1,64 @@
+using LiteCqrs;
+using TeleWave.Api.Common;
+using TeleWave.Application.Library.Interstitials;
+using TeleWave.Application.Library.Interstitials.ImportInterstitials;
+using TeleWave.Application.Library.Interstitials.ListInterstitialBlocks;
+using TeleWave.Application.Library.Interstitials.ListInterstitials;
+using TeleWave.Infrastructure.Identity;
+
+namespace TeleWave.Api.Endpoints;
+
+/// <summary>
+/// Ролики-врезки: тот же <c>Show(Kind = Interstitial)</c>, но со своим экраном (см. 6.7). Правка
+/// названия и удаление идут через обычные эндпоинты шоу — здесь только то, чего у библиотеки нет:
+/// список с длительностями, блоки и импорт загруженных файлов.
+/// </summary>
+public static class InterstitialEndpoints
+{
+    public static IEndpointRouteBuilder MapInterstitialEndpoints(this IEndpointRouteBuilder app)
+    {
+        var admin = app.MapGroup("/api/admin/interstitials")
+            .WithTags("Admin.Interstitials")
+            .RequireAuthorization(policy => policy.RequireRole(RoleNames.Admin));
+
+        admin.MapGet("", List).Produces<IReadOnlyList<InterstitialDto>>();
+        admin.MapGet("/blocks", ListBlocks).Produces<IReadOnlyList<InterstitialBlockDto>>();
+        admin.MapPost("/import", Import).Produces<ImportInterstitialsResponse>();
+
+        return app;
+    }
+
+    private static async Task<IResult> List(ISender sender, CancellationToken cancellationToken)
+    {
+        var result = await sender.Send(new ListInterstitialsQuery(), cancellationToken);
+        return Results.Ok(result);
+    }
+
+    private static async Task<IResult> ListBlocks(
+        ISender sender,
+        CancellationToken cancellationToken
+    )
+    {
+        var result = await sender.Send(new ListInterstitialBlocksQuery(), cancellationToken);
+        return Results.Ok(result);
+    }
+
+    private static async Task<IResult> Import(
+        ImportInterstitialsBody body,
+        ISender sender,
+        CancellationToken cancellationToken
+    )
+    {
+        var result = await sender.Send(
+            new ImportInterstitialsCommand(body.MediaAssetIds),
+            cancellationToken
+        );
+        return result.IsSuccess
+            ? Results.Ok(new ImportInterstitialsResponse(result.Value))
+            : result.ToHttpResult();
+    }
+}
+
+public sealed record ImportInterstitialsBody(IReadOnlyList<Guid> MediaAssetIds);
+
+public sealed record ImportInterstitialsResponse(int Imported);