Added a way for organizations to prohibit providers (#1105)

app/MindWork AI Studio/Settings/DataModel/DataApp.cs

@@ -1,5 +1,6 @@
 using System.Linq.Expressions;
 
+using AIStudio.Provider;
 using AIStudio.Tools.PluginSystem;
 
 namespace AIStudio.Settings.DataModel;
@@ -192,6 +193,17 @@ public sealed class DataApp(Expression<Func<Data, DataApp>>? configSelection = n
     /// </summary>
     public bool AllowUserToAddTranscriptionProvider { get; set; } = ManagedConfiguration.Register(configSelection, n => n.AllowUserToAddTranscriptionProvider, true);
 
+    /// <summary>
+    /// The providers an organization prohibited, for LLMs, embeddings, and transcriptions alike.
+    /// </summary>
+    /// <remarks>
+    /// A prohibition names the operator of an API, not a family of models: prohibiting the API of a
+    /// model maker leaves its models reachable through a hub or a self-hosted server. Providers the
+    /// user set up before stay in the settings, so they are back once the prohibition ends, but
+    /// AI Studio neither offers nor contacts them, see SettingsManager.IsProviderProhibited.
+    /// </remarks>
+    public HashSet<LLMProviders> ProhibitedProviders { get; set; } = ManagedConfiguration.Register(configSelection, n => n.ProhibitedProviders, []);
+
     /// <summary>
     /// Should the user be allowed to add mailboxes?
     /// </summary>