Switch the gate from `currentUser.is_admin` to `access.canSeeOrgAdmin`
so Org owners get the same all-keys view (Creator column, creator
filter, `user_id: '*'` default) that platform admins have. Mirrors
the BE's "platform admin OR current-Org owner" gate on listing every
key in scope.
The user picker now fetches `/user-directory` instead of the
admin-only `/users` endpoint, which would 403 Org owners. Rename the
filter placeholder from the misnamed `models.table.filterByName` to
`common.filter.byCreator`.