feat(AppHeader): add notifications click handler and count display

apps/portal/src/app/layouts/PortalLayout.tsx

@@ -255,6 +255,8 @@ export function PortalLayout() {
           userName={displayName || t("app.name")}
           userInitials={initials}
           supportedLanguages={SUPPORTED_LANGUAGES}
+          onNotificationsClick={() => navigate("/notifications")}
+          notificationCount={unseen?.count}
         />
       </AppShell.Header>