feat: enhance UI and functionality across chat and settings

- Added custom scrollbar styles for improved aesthetics and usability across the interface.
- Implemented responsive adjustments for chat sidebar and input components to enhance mobile experience.
- Integrated tooltip components in select elements for better user guidance and information display.
- Updated chat input and message components for improved styling and functionality.
- Enhanced settings page with semantic query expansion options and improved model selection UI.
- Refactored sidebar list to include better date formatting and tooltip support for session titles.
- Introduced GPU stats monitoring in the system panel for better hardware insights.

components/chat/chat-message.tsx

@@ -123,3 +123,5 @@ export function ChatMessage({ message, isStreaming = false }: ChatMessageProps)
   );
 }
 
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