Fixed and improved the system prompt of chats started from assistants (#1172)

app/MindWork AI Studio/Assistants/Builder/AssistantBuilder.razor.cs

@@ -36,6 +36,9 @@ public partial class AssistantBuilder : AssistantBaseCore<SettingsDialogAssistan
     
     protected override string Description => T("Describe the assistant you want to create. AI Studio will draft a readable assistant specification first and then generate an assistant plugin from it.");
     
+    // This assistant generates a plugin and has no conversation for a chat to continue:
+    protected override ChatSystemPromptChoice ChatSystemPrompt => ChatSystemPromptChoice.AI_STUDIO_DEFAULT;
+
     protected override string SystemPrompt =>
         $"""
          You are the Assistant Builder inside MindWork AI Studio.
@@ -72,7 +75,10 @@ public partial class AssistantBuilder : AssistantBaseCore<SettingsDialogAssistan
     protected override bool ShowResult => false;
     
     protected override bool ShowEntireChatThread => false;
-    
+
+    // Nothing to send: the plugin is installed by this assistant, and there is no conversation for a chat to continue:
+    protected override bool ShowSendTo => false;
+
     protected override bool AllowProfiles => false;
     
     protected override bool ShowProfileSelection => false;