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.

src-tauri/Cargo.toml

@@ -45,3 +45,4 @@ regex = "1.10"
 walkdir = "2.5"
 tauri-plugin-autostart = "2"
 dirs = "5.0"
+rfd = "0.14"