Chore: add a null guard for sidebar hidden items

src-ui/src/app/services/settings.service.spec.ts

@@ -260,6 +260,18 @@ describe('SettingsService', () => {
     ).toBe(false)
   })
 
+  it('handles null values for sidebar hidden items', () => {
+    httpTestingController
+      .expectOne(`${environment.apiBaseUrl}ui_settings/`)
+      .flush(ui_settings)
+
+    settingsService.set(SETTINGS_KEYS.SIDEBAR_HIDDEN_ITEMS, null)
+
+    expect(
+      settingsService.sidebarItemIsHidden(HideableSidebarItemID.Workflows)
+    ).toBe(false)
+  })
+
   it('updates setting signals when settings are reinitialized', () => {
     let req = httpTestingController.expectOne(
       `${environment.apiBaseUrl}ui_settings/`

src-ui/src/app/services/settings.service.ts

@@ -765,7 +765,9 @@ export class SettingsService {
 
   sidebarItemIsHidden(item: HideableSidebarItemID): boolean {
     return (
-      this.sidebarHiddenItemsEditing() ?? this.hiddenSidebarItems()
+      this.sidebarHiddenItemsEditing() ??
+      this.hiddenSidebarItems() ??
+      []
     ).includes(item)
   }
 
@@ -774,7 +776,7 @@ export class SettingsService {
     visible: boolean
   ): void {
     const hiddenItems = new Set(
-      this.sidebarHiddenItemsEditing() ?? this.hiddenSidebarItems()
+      this.sidebarHiddenItemsEditing() ?? this.hiddenSidebarItems() ?? []
     )
     if (visible) {
       hiddenItems.delete(item)