Add navigation dropdown tracking events

Adds two new events for tracking navigation dropdown interactions:

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

ClickedNavigationDropdownItem - typed interface for dropdown clicks
  {
    action: "click",
    flow: "Header",
    context_module: "HeaderArtworksDropdown",
    context_page_owner_type: "home",
    parent_navigation_item: "Artworks",
    dropdown_group: "Blue-Chip Artists",
    subject: "Banksy",
    destination_path: "/artist/banksy"
  }

Author: dblandin

src/Schema/Events/Click.ts

@@ -2698,3 +2698,50 @@ export interface ClickedHeader {
   context_page_owner_type: PageOwnerType
   subject: string
 }
+
+/**
+ * User clicks an item within a navigation dropdown 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 [[ClickedNavigationDropdownItem]]
+ *
+ *  @example Desktop - clicking "Banksy" from the Blue-Chip Artists group:
+ *  ```
+ *  {
+ *    action: "click",
+ *    flow: "Header",
+ *    context_module: "HeaderArtworksDropdown",
+ *    context_page_owner_type: "home",
+ *    parent_navigation_item: "Artworks",
+ *    dropdown_group: "Blue-Chip Artists",
+ *    subject: "Banksy",
+ *    destination_path: "/artist/banksy"
+ *  }
+ *  ```
+ *
+ *  @example Desktop - clicking "View All Artists":
+ *  ```
+ *  {
+ *    action: "click",
+ *    flow: "Header",
+ *    context_module: "HeaderArtistsDropdown",
+ *    context_page_owner_type: "home",
+ *    parent_navigation_item: "Artists",
+ *    subject: "View All Artists",
+ *    destination_path: "/artists"
+ *  }
+ *  ```
+ */
+export interface ClickedNavigationDropdownItem {
+  action: "click"
+  flow: string
+  context_module: ContextModule
+  context_page_owner_type: PageOwnerType
+  context_page_owner_id?: string
+  context_page_owner_slug?: string
+  parent_navigation_item: string
+  dropdown_group?: string
+  subject: 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 dropdown 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 [[NavigationDropdownViewed]].
+ *
+ *  @example Desktop hover:
+ *  ```
+ *  {
+ *    action: "navigationDropdownViewed",
+ *    context_module: "header",
+ *    context_page_owner_type: "home",
+ *    navigation_item: "Artists",
+ *    interaction_type: "hover"
+ *  }
+ *  ```
+ *
+ *  @example Mobile web drilldown:
+ *  ```
+ *  {
+ *    action: "navigationDropdownViewed",
+ *    context_module: "header",
+ *    context_page_owner_type: "artist",
+ *    navigation_item: "Artists",
+ *    interaction_type: "drilldown"
+ *  }
+ *  ```
+ */
+export interface NavigationDropdownViewed {
+  action: ActionType.navigationDropdownViewed
+  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

@@ -187,6 +187,7 @@ import {
   ImmersiveViewArtworkDisplayed,
   ImmersiveViewOptionViewed,
   ItemViewed,
+  NavigationDropdownViewed,
   OrderDetailsViewed,
   OrderProgressionViewed,
   ProgressiveOnboardingTooltipViewed,
@@ -460,6 +461,7 @@ export type Event =
   | ItemViewed
   | MaxBidSelected
   | MyCollectionOnboardingCompleted
+  | NavigationDropdownViewed
   | OnboardingUserInputData
   | OrderDetailsViewed
   | OrderProgressionViewed
@@ -1263,6 +1265,10 @@ export enum ActionType {
    * Corresponds to {@link MyCollectionOnboardingCompleted}
    */
   myCollectionOnboardingCompleted = "myCollectionOnboardingCompleted",
+  /**
+   * Corresponds to {@link NavigationDropdownViewed}
+   */
+  navigationDropdownViewed = "navigationDropdownViewed",
   /**
    * Corresponds to {@link OnboardingUserInputData}
    */