feat: Enhance AgentChatWidget with Chat Session Management and UI Improvements

- Implemented functionality to save, load, and delete chat sessions, allowing users to manage their chat history effectively.
- Introduced a new layout for the connection status bar and improved the AI provider selection interface for better visibility.
- Enhanced the UI of the AgentEditor with a modular 3-column layout, including dedicated tabs for system prompts and common tiles, improving user experience and organization.

src/app/editor/agent/agent_editor.h

@@ -182,6 +182,8 @@ class AgentEditor : public Editor {
   void DrawBotProfilesPanel();
   void DrawChatHistoryViewer();
   void DrawAdvancedMetricsPanel();
+  void DrawCommonTilesEditor();
+  void DrawNewPromptCreator();
 
   // Setup callbacks
   void SetupChatWidgetCallbacks();
@@ -213,8 +215,11 @@ class AgentEditor : public Editor {
   
   // System Prompt Editor
   std::unique_ptr<TextEditor> prompt_editor_;
+  std::unique_ptr<TextEditor> common_tiles_editor_;
   bool prompt_editor_initialized_ = false;
+  bool common_tiles_initialized_ = false;
   std::string active_prompt_file_ = "system_prompt_v3.txt";
+  char new_prompt_name_[128] = {};
   
   // Collaboration state
   CollaborationMode current_mode_ = CollaborationMode::kLocal;