Add CreateTemplate endpoint and related functionality for channels without grids

Implement a new API endpoint to create a template for channels lacking a grid, enhancing the template management capabilities. Update frontend components to support the creation of templates directly from the channel detail view, including user feedback and translations for improved clarity. Add integration tests to ensure the new functionality works as expected.

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

@@ -6,6 +6,7 @@ using TeleWave.Application.Programming.Planning.Preview;
 using TeleWave.Application.Programming.Templates;
 using TeleWave.Application.Programming.Templates.CopyTemplate;
 using TeleWave.Application.Programming.Templates.CreateSlot;
+using TeleWave.Application.Programming.Templates.CreateTemplate;
 using TeleWave.Application.Programming.Templates.DeleteSlot;
 using TeleWave.Application.Programming.Templates.GetTemplate;
 using TeleWave.Application.Programming.Templates.Layers;
@@ -30,6 +31,10 @@ public static class TemplateEndpoints
         admin
             .MapGet("/channels/{channelId:guid}/template", GetTemplate)
             .Produces<ScheduleTemplateDto>();
+        // Завести сетку каналу, у которого её нет (напр. пережившему снос старой ротации).
+        admin
+            .MapPost("/channels/{channelId:guid}/template", CreateTemplate)
+            .Produces<CreatedIdResponse>(StatusCodes.Status201Created);
         admin
             .MapPut("/templates/{templateId:guid}", UpdateTemplate)
             .Produces(StatusCodes.Status204NoContent);
@@ -81,6 +86,24 @@ public static class TemplateEndpoints
         return result.ToHttpResult();
     }
 
+    private static async Task<IResult> CreateTemplate(
+        Guid channelId,
+        ISender sender,
+        CancellationToken cancellationToken
+    )
+    {
+        var result = await sender.Send(
+            new CreateChannelTemplateCommand(channelId),
+            cancellationToken
+        );
+        return result.IsSuccess
+            ? Results.Created(
+                $"/api/admin/channels/{channelId}/template",
+                new CreatedIdResponse(result.Value)
+            )
+            : result.ToHttpResult();
+    }
+
     private static async Task<IResult> ApplyTemplate(
         Guid channelId,
         ISender sender,