feat: Add support for flyout menu mode in MegaMenu

- 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.

src/extensions/megaMenu/MegaMenuApplicationCustomizer.ts

@@ -15,6 +15,7 @@ import { TaxonomyNavigationService } from '../../services/TaxonomyNavigationServ
 import { MegaMenuRenderer } from './MegaMenuRenderer';
 import { IMenuItem } from '../../services/IMenuItem';
 import { debugError, debugLog, debugWarn } from '../../services/MegaMenuDebug';
+import { MegaMenuMode, normalizeMegaMenuMode } from './MegaMenuMode';
 
 import './MegaMenu.module.scss';
 
@@ -26,6 +27,7 @@ export interface IMegaMenuApplicationCustomizerProperties {
   termSetId?: string;
   cacheMinutes?: number;
   debug?: boolean;
+  menuMode?: MegaMenuMode;
 }
 
 export default class MegaMenuApplicationCustomizer
@@ -40,7 +42,7 @@ export default class MegaMenuApplicationCustomizer
     const debug: boolean = this._isDebugEnabled();
     debugLog(debug, LOG_SOURCE, 'onInit started.', {
       componentId: UserCustomActionMegaMenuId,
-      version: '2.0.1',
+      version: '2.1.0',
       properties: this.properties || {},
       pageUrl: window.location.href,
       webUrl: this.context.pageContext.web.absoluteUrl,
@@ -92,7 +94,8 @@ export default class MegaMenuApplicationCustomizer
 
       debugLog(debug, LOG_SOURCE, 'Starting MegaMenu rendering.', {
         termSetIdentifier: termSetIdentifier,
-        cacheMinutes: this._getCacheMinutes()
+        cacheMinutes: this._getCacheMinutes(),
+        menuMode: this._getMenuMode()
       });
       this._renderMegaMenu(termSetIdentifier, debug);
     } else {
@@ -127,7 +130,8 @@ export default class MegaMenuApplicationCustomizer
 
       this._renderer = new MegaMenuRenderer(
         menuItems,
-        debug
+        debug,
+        this._getMenuMode()
       );
 
       this._menuContainer = this._getOrCreateContainer('CustomHeader', this._topPlaceholder);
@@ -205,6 +209,10 @@ export default class MegaMenuApplicationCustomizer
     return isFinite(value) ? Math.min(Math.max(Math.floor(value), 1), 1440) : 15;
   }
 
+  private _getMenuMode(): MegaMenuMode {
+    return normalizeMegaMenuMode(this.properties && this.properties.menuMode);
+  }
+
   private _renderStatus(message: string): void {
     if (!this._topPlaceholder) {
       return;