Each font row holds a family picker and a px dropdown side by side, with
the live preview full-width underneath. The family picker enumerates
every installed font through the Local Font Access API (searchable,
virtualized, monospace-gated for grid surfaces); engines without the
API get a plain validated name input instead of the old curated
catalog, which leaves with this commit. The desktop preview browser
session now grants local-fonts so embedded T3 tabs can enumerate too.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>