feat: add navigation submenu tracking events

Adds two new events for tracking navigation submenu interactions:

navigationSubmenuViewed - fires when submenu is displayed
  {
    action: "navigationSubmenuViewed",
    context_module: "header",
    context_page_owner_type: "home",
    navigation_item: "Artists",
    interaction_type: "hover"
  }

clickedNavigationSubmenuItem - fires when submenu item is clicked
  {
    action: "clickedNavigationSubmenuItem",
    context_module: "header",
    context_page_owner_type: "home",
    parent_navigation_item: "Artists",
    submenu_group: "Blue-Chip Artists",
    submenu_item: "Banksy",
    destination_path: "/artist/banksy"
  }

Author: dblandin

src/Schema/Events/Click.ts

@@ -2698,3 +2698,47 @@ export interface ClickedHeader {
   context_page_owner_type: PageOwnerType
   subject: string
 }
+
+/**
+ * User clicks an item within a navigation submenu on web (desktop or mobile)
+ * Triggered before navigation to the destination
+ * Note: Clicks on actual items (e.g., "Banksy"), not category headings (e.g., "Blue-Chip Artists")
+ *
+ * This schema describes events sent to Segment from [[ClickedNavigationSubmenuItem]]
+ *
+ *  @example Desktop - clicking "Banksy" from the Blue-Chip Artists group:
+ *  ```
+ *  {
+ *    action: "clickedNavigationSubmenuItem",
+ *    context_module: "header",
+ *    context_page_owner_type: "home",
+ *    parent_navigation_item: "Artists",
+ *    submenu_group: "Blue-Chip Artists",
+ *    submenu_item: "Banksy",
+ *    destination_path: "/artist/banksy"
+ *  }
+ *  ```
+ *
+ *  @example Desktop - clicking "View All Artists":
+ *  ```
+ *  {
+ *    action: "clickedNavigationSubmenuItem",
+ *    context_module: "header",
+ *    context_page_owner_type: "home",
+ *    parent_navigation_item: "Artists",
+ *    submenu_item: "View All Artists",
+ *    destination_path: "/artists"
+ *  }
+ *  ```
+ */
+export interface ClickedNavigationSubmenuItem {
+  action: ActionType.clickedNavigationSubmenuItem
+  context_module: ContextModule
+  context_page_owner_type: PageOwnerType
+  context_page_owner_id?: string
+  context_page_owner_slug?: string
+  parent_navigation_item: string
+  submenu_group?: string
+  submenu_item: string
+  destination_path: string
+}

src/Schema/Events/ImpressionTracking.ts

@@ -550,3 +550,42 @@ export interface ImmersiveViewArtworkDisplayed {
   context_page_owner_id?: string
   artwork_id: string
 }
+
+/**
+ * User views a navigation submenu on web
+ * - Desktop: triggered after hovering over a top-level nav item (e.g., "Artists") with delay
+ * - Mobile web: triggered when drilling down into the navigation menu hierarchy
+ *
+ * This schema describes events sent to Segment from [[NavigationSubmenuViewed]].
+ *
+ *  @example Desktop hover:
+ *  ```
+ *  {
+ *    action: "navigationSubmenuViewed",
+ *    context_module: "header",
+ *    context_page_owner_type: "home",
+ *    navigation_item: "Artists",
+ *    interaction_type: "hover"
+ *  }
+ *  ```
+ *
+ *  @example Mobile web drilldown:
+ *  ```
+ *  {
+ *    action: "navigationSubmenuViewed",
+ *    context_module: "header",
+ *    context_page_owner_type: "artist",
+ *    navigation_item: "Artists",
+ *    interaction_type: "drilldown"
+ *  }
+ *  ```
+ */
+export interface NavigationSubmenuViewed {
+  action: ActionType.navigationSubmenuViewed
+  context_module: ContextModule
+  context_page_owner_type: PageOwnerType
+  context_page_owner_id?: string
+  context_page_owner_slug?: string
+  navigation_item: string
+  interaction_type: "hover" | "drilldown"
+}

src/Schema/Events/index.ts

@@ -88,6 +88,7 @@ import {
   ClickedMarkSold,
   ClickedMarkSpam,
   ClickedNavBar,
+  ClickedNavigationSubmenuItem,
   ClickedNavigationTab,
   ClickedOfferActions,
   ClickedOfferOption,
@@ -187,6 +188,7 @@ import {
   ImmersiveViewArtworkDisplayed,
   ImmersiveViewOptionViewed,
   ItemViewed,
+  NavigationSubmenuViewed,
   OrderDetailsViewed,
   OrderProgressionViewed,
   ProgressiveOnboardingTooltipViewed,
@@ -381,6 +383,7 @@ export type Event =
   | ClickedMarkSpam
   | ClickedNavBar
   | ClickedNavigationTab
+  | ClickedNavigationSubmenuItem
   | ClickedNotificationsBell
   | ClickedOfferActions
   | ClickedOfferOption
@@ -460,6 +463,7 @@ export type Event =
   | ItemViewed
   | MaxBidSelected
   | MyCollectionOnboardingCompleted
+  | NavigationSubmenuViewed
   | OnboardingUserInputData
   | OrderDetailsViewed
   | OrderProgressionViewed
@@ -854,6 +858,10 @@ export enum ActionType {
    * Corresponds to {@link ClickedNavigationTab}
    */
   clickedNavigationTab = "clickedNavigationTab",
+  /**
+   * Corresponds to {@link ClickedNavigationSubmenuItem}
+   */
+  clickedNavigationSubmenuItem = "clickedNavigationSubmenuItem",
   /**
    * Corresponds to {@link ClickedNotificationsBell}
    */
@@ -1263,6 +1271,10 @@ export enum ActionType {
    * Corresponds to {@link MyCollectionOnboardingCompleted}
    */
   myCollectionOnboardingCompleted = "myCollectionOnboardingCompleted",
+  /**
+   * Corresponds to {@link NavigationSubmenuViewed}
+   */
+  navigationSubmenuViewed = "navigationSubmenuViewed",
   /**
    * Corresponds to {@link OnboardingUserInputData}
    */