Add language-aware article sorting

tests/Jellyfin.Plugin.Multilang.Tests/ItemsProxyTransformerResolutionTests.cs

@@ -29,6 +29,7 @@ public sealed class ItemsProxyTransformerResolutionTests
 
         Assert.True(result.Change);
         Assert.Equal("Finnish overview", result.Value);
+        Assert.Equal("fi", result.Language);
     }
 
     [Fact]
@@ -37,11 +38,12 @@ public sealed class ItemsProxyTransformerResolutionTests
         var result = ItemsProxyTransformer.ResolveField(
             TitleField,
             [OriginalAction, LanguagePrefix + "en"],
-            Facts(originalTitle: "Original title"),
+            Facts(originalTitle: "Original title", originalLanguage: "en"),
             TextTranslations(("en", TitleField, "English title")));
 
         Assert.True(result.Change);
         Assert.Equal("Original title", result.Value);
+        Assert.Equal("en", result.Language);
     }
 
     [Fact]
@@ -55,6 +57,7 @@ public sealed class ItemsProxyTransformerResolutionTests
 
         Assert.False(result.Change);
         Assert.Null(result.Value);
+        Assert.Null(result.Language);
     }
 
     [Fact]
@@ -145,13 +148,13 @@ public sealed class ItemsProxyTransformerResolutionTests
         return result;
     }
 
-    private static FactsData Facts(string originalTitle = "")
+    private static FactsData Facts(string originalTitle = "", string originalLanguage = "")
         => new(
             "item",
             "tmdb",
             "movie",
             originalTitle,
-            "",
+            originalLanguage,
             "",
             "[]",
             "[]",