- Introduced `MegaMenuMode` type and `normalizeMegaMenuMode` function to handle menu modes.
- Updated `MegaMenuApplicationCustomizer` to accept `menuMode` property.
- Enhanced `MegaMenuRenderer` to render flyout menus based on the selected mode.
- Created new HTML previews for both flyout and mega menu modes.
- Removed unused mock services and user custom action service interfaces.