Let people change the embedding of an indexed data source

app/MindWork AI Studio/Tools/Services/DataSourceEmbeddingService.cs

@@ -199,12 +199,30 @@ public sealed partial class DataSourceEmbeddingService(SettingsManager settingsM
             this.CanRefreshDataSource(dataSource);
     }
 
-    public async Task<bool> ShouldLockDataSourceIdentityAsync(string dataSourceId, CancellationToken token = default)
+    /// <summary>
+    /// Whether the file or folder a data source reads must stay as it is.
+    /// </summary>
+    /// <remarks>
+    /// Locked as soon as the index holds anything, because where a data source reads from is what it
+    /// is: another folder is another data source, and the path reaches no signature, so swapping it
+    /// would leave the stored index describing documents nobody points at any more.
+    ///
+    /// The embedding provider used to be locked along with it and no longer is. It does reach the
+    /// signature, so changing it rebuilds the index cleanly -- and DataSourceReindexWarning asks
+    /// before it does. Locking it as well left a data source whose provider was deleted stuck on
+    /// keyword search for good, with no way back.
+    ///
+    /// Unclear counts as locked: an unavailable index database says nothing about what is stored.
+    /// </remarks>
+    /// <param name="dataSourceId">The data source to ask about.</param>
+    /// <param name="token">The cancellation token.</param>
+    /// <returns>True when the source must not be changed.</returns>
+    public async Task<bool> ShouldLockDataSourceOriginAsync(string dataSourceId, CancellationToken token = default)
     {
         var indexStore = await databaseClientProvider.GetIndexStoreAsync(token);
         if (!indexStore.IsAvailable)
         {
-            logger.LogWarning("Locking identity settings for data source '{DataSourceId}' because the local RAG index database '{DatabaseName}' is unavailable.", dataSourceId, indexStore.Name);
+            logger.LogWarning("Locking the source of data source '{DataSourceId}' because the local RAG index database '{DatabaseName}' is unavailable.", dataSourceId, indexStore.Name);
             return true;
         }