feat: Enhance Agent Editor and Chat History Management

- Added support for internal message handling in the AgentChatHistoryCodec, allowing messages marked as internal to be excluded from user display.
- Updated the AgentChatWidget to skip rendering internal messages, improving user experience by reducing clutter.
- Introduced a comprehensive bot profile management system in the AgentEditor, enabling users to create, save, load, and manage bot profiles with detailed configurations.
- Enhanced the UI for the AgentEditor, including a new tabbed interface for better organization of settings, prompts, and profiles, along with improved metrics and chat history viewing capabilities.
- Implemented JSON support for bot profile management, allowing for easy export and import of profiles, streamlining user workflows.

src/app/editor/agent/agent_chat_widget.cc

@@ -324,6 +324,11 @@ void AgentChatWidget::HandleAgentResponse(
 }
 
 void AgentChatWidget::RenderMessage(const ChatMessage& msg, int index) {
+  // Skip internal messages (tool results meant only for the LLM)
+  if (msg.is_internal) {
+    return;
+  }
+  
   ImGui::PushID(index);
 
   const bool from_user = (msg.sender == ChatMessage::Sender::kUser);