Fix implemented via PR #510

What was done:

Dashboard_Widgets::enqueue_scripts() now explicitly enqueues wu-functions on the network admin dashboard. The dashboard (index.php) is not a wp-ultimo page, so enqueue_default_admin_scripts() skips it — wu-functions.js (which defines window.wu_moment) was never loaded, causing the activity stream widget to fail with wu_moment is not defined and show only Vue placeholders.
wu_moment() in functions.js now falls back to plain moment() when moment.tz is unavailable. WordPress bundles moment.js but not moment-timezone, so moment.tz was always undefined on standard installs.
activity-stream.php now declares wu-functions as a dependency of wu-activity-stream to enforce correct load order.

Testing Evidence:

Testing level: self-assessed — no runtime environment available; change is a missing script dependency and a defensive fallback
Stability results: All CI checks pass (PHP 8.2–8.5, Cypress E2E, Code Quality, Performance)
Smoke pages/endpoints checked: N/A — no dev server available

Key decisions:

Added wu-functions as both an explicit enqueue in enqueue_scripts() AND as a dependency in the template — belt-and-suspenders, since either alone would fix the issue but both together are more robust
Used typeof moment.tz === 'function' guard rather than removing the moment.tz call entirely, preserving timezone-aware behaviour when moment-timezone is available

Files changed:

inc/class-dashboard-widgets.php — enqueue wu-functions on dashboard
assets/js/functions.js + functions.min.js — wu_moment fallback for missing moment.tz
views/dashboard-widgets/activity-stream.php — add wu-functions as script dependency

Blockers encountered: None
Follow-up needs: None — PR #510 awaiting human review approval

Widget failing to render on network admin dashboard #509