Read the context window from a provider's model list

app/MindWork AI Studio/Models/Live/ModelListing.cs

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+namespace AIStudio.Models.Live;
+
+/// <summary>
+/// What a provider's own model list says about one of the models it serves.
+/// </summary>
+/// <remarks>
+/// That list is fetched anyway: before every chat round, before every assistant run, and whenever
+/// somebody opens the provider dialog. Reading what it already carries therefore costs no request
+/// of its own, which is the whole reason these numbers are taken from here and not asked for.
+///
+/// This describes one installation, never the model as such. Two machines may serve the same
+/// weights behind different settings, and a statement about one of them says nothing about the
+/// other -- which is why a listing is kept per configured provider instance and is gone with the
+/// process. It is also the only source for a self-hosted model: a rule can say what the weights
+/// were trained for, but only the engine knows what its operator started it with.
+/// </remarks>
+/// <param name="ModelId">The model, named the way the provider names it in its list.</param>
+/// <param name="Context">The window the provider states for it, or unknown where it states none.</param>
+public readonly record struct ModelListing(string ModelId, ContextWindow Context)
+{
+    /// <summary>
+    /// What we have about a model nobody has reported anything about.
+    /// </summary>
+    public static readonly ModelListing NOTHING = new(string.Empty, ContextWindow.UNKNOWN);
+
+    /// <summary>
+    /// Whether this listing states anything at all.
+    /// </summary>
+    public bool IsKnown => this.Context.IsKnown;
+
+    /// <summary>
+    /// Puts what the provider stated over what the rules worked out.
+    /// </summary>
+    /// <remarks>
+    /// A stated window replaces the whole window, the ceiling included, for the same reason the
+    /// expert settings do: what a model card says it could be raised to is a statement about the
+    /// model, while this is a statement about the installation serving it. Whoever started that
+    /// engine has already decided, and a ceiling nobody can reach without restarting it is not a
+    /// number to keep showing.
+    /// </remarks>
+    /// <param name="profile">What is known about the model without this listing.</param>
+    /// <returns>The profile, with what the provider stated in it.</returns>
+    public ModelProfile ApplyTo(in ModelProfile profile) => this.IsKnown ? profile with { Context = this.Context } : profile;
+}