docs(docs-infra): preserve navigation origin when clicking cross-category links

When a sidebar item links to a page in a different category (e.g., Route
transition animations under Animations links to a Routing page), clicking
back navigates to the main menu instead of the originating category.

Store the originating category in NavigationState when clicking a
cross-referenced item, so the back button returns to the correct section.

Author: erkamyaman

adev/shared-docs/components/navigation-list/navigation-list.component.html

@@ -53,7 +53,7 @@
                   matrixParams: 'ignored',
                   fragment: 'ignored',
                 }"
-                (click)="emitClickOnLink()"
+                (click)="emitClickOnLink(item)"
                 [matTooltip]="item.label"
                 [matTooltipDisabled]="itemLabel.length < 27"
                 matTooltipPosition="after"

adev/shared-docs/components/navigation-list/navigation-list.component.spec.ts

@@ -153,5 +153,6 @@ describe('NavigationList', () => {
 class FakeNavigationListState {
   isOpened = signal(true);
   activeNavigationItem = signal(navigationItems.at(1));
+  crossCategoryOrigin = signal<NavigationItem | undefined>(undefined);
   toggleItem(item: NavigationItem) {}
 }

adev/shared-docs/components/navigation-list/navigation-list.component.ts

@@ -39,6 +39,7 @@ export class NavigationList {
   readonly linkClicked = output<void>();
 
   private readonly navigationState = inject(NavigationState);
+  private readonly crossCategoryOrigin = this.navigationState.crossCategoryOrigin;
 
   readonly activeItem = this.navigationState.activeNavigationItem;
 
@@ -50,10 +51,19 @@ export class NavigationList {
     ) {
       return;
     }
+    const prevParentItem = this.crossCategoryOrigin();
+    if (prevParentItem) {
+      this.crossCategoryOrigin.set(undefined);
+      this.navigationState.toggleItem(prevParentItem);
+      return;
+    }
     this.navigationState.toggleItem(item);
   }
 
-  emitClickOnLink(): void {
+  emitClickOnLink(item: NavigationItem): void {
+    if (item.isCrossReferenced) {
+      this.crossCategoryOrigin.set(item.parent);
+    }
     this.linkClicked.emit();
   }
 

adev/shared-docs/interfaces/navigation-item.ts

@@ -17,5 +17,6 @@ export interface NavigationItem {
   contentPath?: string;
   status?: 'new' | 'updated';
   category?: string;
+  isCrossReferenced?: boolean;
   preserveOtherCategoryOrder?: boolean; // true by default
 }

adev/shared-docs/services/navigation-state.service.ts

@@ -21,6 +21,7 @@ export class NavigationState {
   private readonly _isMobileNavVisible = signal<boolean>(false);
   private readonly _level = linkedSignal(() => this._expandedItems().length);
 
+  readonly crossCategoryOrigin = signal<NavigationItem | undefined>(undefined);
   readonly primaryActiveRouteItem = signal<string | null>(null);
   activeNavigationItem = this._activeNavigationItem.asReadonly();
   expandedItems = this._expandedItems.asReadonly();

adev/src/app/routing/navigation-entries/index.ts

@@ -660,6 +660,7 @@ export const DOCS_SUB_NAVIGATION_DATA: NavigationItem[] = [
             path: 'guide/routing/testing',
             contentPath: 'guide/routing/testing',
             status: 'new',
+            isCrossReferenced: true,
           },
           {
             label: 'Debugging tests',
@@ -863,6 +864,7 @@ export const DOCS_SUB_NAVIGATION_DATA: NavigationItem[] = [
             label: 'Route transition animations',
             path: 'guide/routing/route-transition-animations',
             contentPath: 'guide/routing/route-transition-animations',
+            isCrossReferenced: true,
           },
         ],
       },