Add one model host per provider and the unwrapping walk

app/MindWork AI Studio/Models/Hosting/Hosts/HostOpenRouter.cs

@@ -0,0 +1,25 @@
+using AIStudio.Models.Matching;
+using AIStudio.Provider;
+
+namespace AIStudio.Models.Hosting.Hosts;
+
+/// <summary>
+/// OpenRouter, which serves other people's models and says whose they are.
+/// </summary>
+/// <remarks>
+/// The vendor prefix is the reason the old rules delegated between vendors in circles: a name such
+/// as "anthropic/claude-opus-5" had to be handed to whoever knew Claude, and the same for every
+/// other vendor. Here the prefix is simply taken off, and the vendor stated, and one set of rules
+/// answers the bare name -- no matter which provider it arrived from.
+/// </remarks>
+public sealed class HostOpenRouter : ModelHost
+{
+    /// <inheritdoc />
+    public override LLMProviders Provider => LLMProviders.OPEN_ROUTER;
+
+    /// <inheritdoc />
+    public override ModelSource Source => new("https://openrouter.ai/docs/api-reference/overview", new DateOnly(2026, 9, 11), "Models are named \"vendor/model\", and every one of them is served through the OpenAI-compatible chat completion API.");
+
+    /// <inheritdoc />
+    public override bool TryUnwrap(in ModelId id, out ModelId inner, out ModelVendor? declaredVendor) => HostNaming.TrySplitOrganization(id, out inner, out declaredVendor);
+}