Sidebar navigation for the admin shell.
Renders static, always-visible nav groups (Billing, Recovery, Developer,
Catalog, Connect) with status-toned attention-count badges on group headers.
There are no collapse toggles or chevrons — every group's link list is always
shown, and navigation is client-side live navigation via <.link navigate>.
Group rendering rules
- Each group renders a static
<p>label (nil group → no label). - The label carries an optional status-toned badge when
group_meta.badgeis a positive integer. - Link list always renders in
<div id="sidebar-group-links-{slug}">.