fix(auth): allow admins to change any username including their own

apps/web/src/pages/admin/AuditPage.tsx

@@ -15,6 +15,7 @@ type Entry = components['schemas']['AuditEntry'];
 function details(e: Entry, roleName: (r: string) => string): string {
   const p = e.payload ?? {};
   if (e.action === 'user.role_change') return `${roleName(String(p.from))} → ${roleName(String(p.to))}`;
+  if (e.action === 'user.username_change') return `${String(p.from)} → ${String(p.to)}`;
   const parts = [p.username, p.role && roleName(String(p.role)), p.display_name].filter(
     (v): v is string => typeof v === 'string' && v !== '',
   );