Port the Mistral families, including the release date logic

app/MindWork AI Studio/Models/Mistral/CodestralFamily.cs

@@ -0,0 +1,27 @@
+using static AIStudio.Provider.Capability;
+
+namespace AIStudio.Models.Mistral;
+
+/// <summary>
+/// Codestral, the Mistral models for writing code.
+/// </summary>
+/// <remarks>
+/// The previous rules never named it. Its name contains neither "mistral" nor any of the other
+/// words the Mistral block looked for, so it walked past every rule and reached the answer meant
+/// for everything nobody had written one for. That answer happened to describe it correctly, which
+/// is why nothing looked wrong -- and is exactly the situation this rebuild is meant to end.
+/// </remarks>
+public sealed class CodestralFamily : ModelFamily
+{
+    /// <inheritdoc />
+    public override ModelVendor Vendor => ModelVendor.MISTRAL_AI;
+
+    /// <inheritdoc />
+    public override ModelSource Source => new("https://docs.mistral.ai/getting-started/models/models_overview/", new DateOnly(2026, 9, 11), "The answer the previous rules gave it through their fallback: text in, text out, tool calling.");
+
+    /// <inheritdoc />
+    protected override void Declare(ModelFamilyBuilder builder) =>
+        builder.Rule("codestral").AsSegment()
+            .Capabilities(TEXT_INPUT | TEXT_OUTPUT | FUNCTION_CALLING)
+            .Apis(CHAT_COMPLETION_API);
+}