The desktop TOC is its own scroll container (overflow-y:auto + max-height),
but unlike article content — which gets trailing space via
.page-content > article::after — it had nothing below the last link. A long
TOC scrolled to the bottom left the final link flush against the edge.
Add .toc::after as a block pseudo-element inside the desktop media query,
using the same technique (and the same Firefox-clips-padding-bottom reason)
as the article. Shared component, so public (about/charte/licence) and admin
(#admin-toc) both get it. Verified with Playwright: 0px -> ~60px gap;
mobile unaffected (TOC is not a scroll container there).
