Module-tier shell bottom chrome bar. Same shape as admin-topbar; conventionally read-only status.
This is a CSS-only structural stub — no JavaScript, no behavior. The shell host (<admin-shell>) styles it via tag-presence. Authors compose it with sibling bespoke children to express semantic shell-tier structure.
Typical placement inside <admin-shell>:
See the admin-shell demo for the full composition pattern. CSS-only stubs declare slot intent; the parent shell handles layout.