Add the model family API, its compile-time registry, and MWAIS0013

app/MindWork AI Studio/Models/ModelSource.cs

@@ -0,0 +1,28 @@
+namespace AIStudio.Models;
+
+/// <summary>
+/// Where the statements about a model were read, and when somebody last looked.
+/// </summary>
+/// <remarks>
+/// Model cards change without telling anybody. A vendor adds tool calling to a checkpoint, raises a
+/// context window, or quietly stops offering an API, and the rule written from the old page keeps
+/// answering as if nothing happened. Naming the page and the day it was read is what turns "this is
+/// what the rules say" into something a person can check in a minute.
+///
+/// This is not optional: a family has to state it, and the compiler asks for it. The verification
+/// run reports the ones which have gone stale.
+/// </remarks>
+/// <param name="Url">The page the statements were read from.</param>
+/// <param name="CheckedOn">The day somebody last read it.</param>
+/// <param name="Note">What that page actually said, in a sentence, so a reader knows what to look for.</param>
+public sealed record ModelSource(string Url, DateOnly CheckedOn, string Note)
+{
+    /// <summary>
+    /// Whether this source names a page and a day.
+    /// </summary>
+    /// <remarks>
+    /// The compiler can insist that a family states a source; it cannot insist that the source says
+    /// anything. This is what the verification run asks.
+    /// </remarks>
+    public bool IsStated => !string.IsNullOrWhiteSpace(this.Url) && this.CheckedOn != default;
+}