Add the model matching engine and make capabilities a flags enum

app/MindWork AI Studio/Models/Matching/ModelRuleKind.cs

@@ -0,0 +1,24 @@
+namespace AIStudio.Models.Matching;
+
+/// <summary>
+/// What a rule does once it matches.
+/// </summary>
+public enum ModelRuleKind
+{
+    /// <summary>
+    /// Chooses which model this is. Exactly one selector wins, the most specific one.
+    /// </summary>
+    SELECTOR,
+
+    /// <summary>
+    /// Adjusts whatever the selector chose. Every matching modifier applies.
+    /// </summary>
+    /// <remarks>
+    /// This is for the statements which hold across families, and which every family would
+    /// otherwise have to repeat: a base checkpoint was never instruction tuned no matter who built
+    /// it, and a gateway serving somebody else's model cannot offer that vendor's own API. In the
+    /// old rules those had to sit at the very top of the file, which is why anything below them
+    /// could not state an exception.
+    /// </remarks>
+    MODIFIER,
+}