Fix image failure response handling in batch endpoint

src/Jellyfin.LiveTv/Listings/SchedulesDirectDtos/ImageDataArrayConverter.cs

@@ -0,0 +1,42 @@
+using System;
+using System.Collections.Generic;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace Jellyfin.LiveTv.Listings.SchedulesDirectDtos;
+
+/// <summary>
+/// Converter for the <c>data</c> field in SD image responses.
+/// The Schedules Direct API may return a non-array value (e.g. a string error message)
+/// instead of the expected image data array for programs with errors.
+/// This converter returns an empty list for any non-array value.
+/// </summary>
+public sealed class ImageDataArrayConverter : JsonConverter<IReadOnlyList<ImageDataDto>>
+{
+    /// <inheritdoc />
+    public override IReadOnlyList<ImageDataDto> Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+    {
+        if (reader.TokenType == JsonTokenType.StartArray)
+        {
+            var result = new List<ImageDataDto>();
+            while (reader.Read() && reader.TokenType != JsonTokenType.EndArray)
+            {
+                var item = JsonSerializer.Deserialize<ImageDataDto>(ref reader, options);
+                if (item is not null)
+                {
+                    result.Add(item);
+                }
+            }
+
+            return result;
+        }
+
+        // Not an array (string error, null, object, etc.) — skip and return empty.
+        reader.Skip();
+        return [];
+    }
+
+    /// <inheritdoc />
+    public override void Write(Utf8JsonWriter writer, IReadOnlyList<ImageDataDto> value, JsonSerializerOptions options)
+        => JsonSerializer.Serialize(writer, value, options);
+}

src/Jellyfin.LiveTv/Listings/SchedulesDirectDtos/ShowImagesDto.cs

@@ -19,6 +19,7 @@ namespace Jellyfin.LiveTv.Listings.SchedulesDirectDtos
         /// Gets or sets the list of data.
         /// </summary>
         [JsonPropertyName("data")]
+        [JsonConverter(typeof(ImageDataArrayConverter))]
         public IReadOnlyList<ImageDataDto> Data { get; set; } = Array.Empty<ImageDataDto>();
     }
 }