Moved the rollback rules into the chat thread

app/MindWork AI Studio/Components/ChatComponent.razor.cs

@@ -1463,21 +1463,11 @@ public partial class ChatComponent : MSGComponentBase
         if (this.ChatThread is null || this.IsCurrentChatStreaming)
             return;
 
-        if (!this.ChatThread.RemoveBlocksAfter(aiBlock))
+        // Which parts of the thread a rollback resets and which it keeps is documented at RollBackTo:
+        if (!this.ChatThread.RollBackTo(aiBlock))
             return;
 
-        //
-        // Only the working state of the next turn is reset here: the augmented data and the
-        // AI-selected data sources are rebuilt by the RAG process anyway, so carrying the ones of a
-        // removed message over would just put stale context into the system prompt.
-        //
-        // What stays is everything the thread ratchets for security reasons, namely DataSecurity and
-        // RequiredProviderConfidence. Both only ever tighten, because the data which raised them was
-        // seen by this thread. Removing the message that brought it in does not unsee it, so the
-        // chat keeps demanding the same of every provider which continues it.
-        //
-        this.ChatThread.AugmentedData = string.Empty;
-        this.ChatThread.AISelectedDataSources = [];
+        // The rollback reset the AI-selected data sources, which the data source selection still shows:
         this.dataSourceSelectionComponent?.ChangeOptionWithoutSaving(this.ChatThread.DataSourceOptions, this.ChatThread.AISelectedDataSources);
         this.hasUnsavedChanges = true;
         await this.SaveThread();