Improved the OpenAI provider (#548)

app/MindWork AI Studio/Provider/Perplexity/ResponseStreamLine.cs

@@ -22,24 +22,4 @@ public readonly record struct ResponseStreamLine(string Id, string Object, uint
 
     /// <inheritdoc />
     public IList<ISource> GetSources() => this.SearchResults.Cast<ISource>().ToList();
-}
-
-/// <summary>
-/// Data model for a choice made by the AI.
-/// </summary>
-/// <param name="Index">The index of the choice.</param>
-/// <param name="Delta">The delta text of the choice.</param>
-public readonly record struct Choice(int Index, Delta Delta);
-
-/// <summary>
-/// The delta text of a choice.
-/// </summary>
-/// <param name="Content">The content of the delta text.</param>
-public readonly record struct Delta(string Content);
-
-/// <summary>
-/// Data model for a search result.
-/// </summary>
-/// <param name="Title">The title of the search result.</param>
-/// <param name="URL">The URL of the search result.</param>
-public sealed record SearchResult(string Title, string URL) : Source(Title, URL);
+}