Port the remaining open weights we decided to name

app/MindWork AI Studio/Models/OpenAI/GptOssFamily.cs

@@ -0,0 +1,30 @@
+using static AIStudio.Provider.Capability;
+
+namespace AIStudio.Models.OpenAI;
+
+/// <summary>
+/// gpt-oss, the weights OpenAI published.
+/// </summary>
+/// <remarks>
+/// The only OpenAI model anybody else may serve, and the reason the rest of this folder does not
+/// have to worry about being confused with it: "gpt-oss" is a name part of its own, while every
+/// cloud model of theirs carries a version behind the "gpt". The previous rules needed a function
+/// to tell the two apart, and it is the specificity which does it here.
+///
+/// It browses through the harmony format it was trained on, which is why web search is stated even
+/// though nothing else among the open weights has it.
+/// </remarks>
+public sealed class GptOssFamily : ModelFamily
+{
+    /// <inheritdoc />
+    public override ModelVendor Vendor => ModelVendor.OPEN_AI;
+
+    /// <inheritdoc />
+    public override ModelSource Source => new("https://huggingface.co/openai/gpt-oss-120b", new DateOnly(2026, 9, 11), "Ported unchanged from the gpt-oss check of ProviderExtensions.OpenSource.cs.");
+
+    /// <inheritdoc />
+    protected override void Declare(ModelFamilyBuilder builder) =>
+        builder.Rule("gpt-oss").AsSegment()
+            .Capabilities(TEXT_INPUT | TEXT_OUTPUT | FUNCTION_CALLING | WEB_SEARCH)
+            .Apis(CHAT_COMPLETION_API);
+}