External Fonts
Declare custom fonts under template.fonts, keyed by family name, each with a src URL (plus
weight/style). Reference the family from any block’s config.typography.family. Everything
else falls back to the bundled typography family.
The example fetches “Lobster” from a public CDN at render time, so the API must have network
access and allow that host (it allows public hosts by default; see ASSET_ALLOWED_DOMAINS).