Added a settings field storing user values before configuration plugins take them over

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

@@ -68,6 +68,18 @@ public sealed class Data
     /// </summary>
     public Dictionary<string, Guid> ManagedLockedConfigurations { get; set; } = [];
 
+    /// <summary>
+    /// The value each managed setting had before a configuration plugin took it over, as JSON.
+    /// </summary>
+    /// <remarks>
+    /// A configuration plugin might be removed later, e.g. when a test configuration ends or when an
+    /// organization withdraws its configuration. The value the user had chosen before belongs to the
+    /// user, so we keep it here and restore it instead of falling back to the app's default value.
+    /// The snapshot is taken once, when a setting becomes managed, and is consumed when no
+    /// configuration plugin manages that setting anymore.
+    /// </remarks>
+    public Dictionary<string, string> ManagedUserValueSnapshots { get; set; } = [];
+
     /// <summary>
     /// Cached audit results for assistant plugins.
     /// </summary>