Add the model matching engine and make capabilities a flags enum

app/MindWork AI Studio/Models/ContextWindow.cs

@@ -0,0 +1,57 @@
+namespace AIStudio.Models;
+
+/// <summary>
+/// How much a model can read and write in one conversation, in tokens.
+/// </summary>
+/// <remarks>
+/// Two numbers, because the model cards name two. There is what the model does as it ships, and
+/// there is what an operator can raise it to by configuring the engine, usually through one of the
+/// rope-scaling settings. A self-hosted model runs at whatever its operator chose, so the second
+/// number is a ceiling, not a promise.
+///
+/// Nothing here says "unknown" with a zero. The default value of this type is unknown, which is the
+/// right answer for a model nobody has written anything about yet, and a known window can never be
+/// zero tokens wide because the factory below refuses to build one.
+/// </remarks>
+public readonly record struct ContextWindow
+{
+    /// <summary>
+    /// The window of a model we have no statement about.
+    /// </summary>
+    public static readonly ContextWindow UNKNOWN = new();
+
+    /// <summary>
+    /// Whether anything is known about this window at all. When false, both numbers are meaningless.
+    /// </summary>
+    public bool IsKnown { get; private init; }
+
+    /// <summary>
+    /// What the model reads and writes without anyone configuring it.
+    /// </summary>
+    public int DefaultTokens { get; private init; }
+
+    /// <summary>
+    /// What an operator can raise the window to, or null when it cannot be raised or nobody knows.
+    /// </summary>
+    public int? RaisableToTokens { get; private init; }
+
+    /// <summary>
+    /// States a known context window.
+    /// </summary>
+    /// <param name="defaultTokens">What the model does as it ships. Has to be greater than zero.</param>
+    /// <param name="raisableTo">What an operator can raise it to. Has to be at least the default.</param>
+    /// <returns>The window.</returns>
+    public static ContextWindow Of(int defaultTokens, int? raisableTo = null)
+    {
+        ArgumentOutOfRangeException.ThrowIfNegativeOrZero(defaultTokens);
+        if (raisableTo is not null)
+            ArgumentOutOfRangeException.ThrowIfLessThan(raisableTo.Value, defaultTokens);
+
+        return new()
+        {
+            IsKnown = true,
+            DefaultTokens = defaultTokens,
+            RaisableToTokens = raisableTo,
+        };
+    }
+}