Licensing: add OFL text for the site webfonts (Inter, Barlow Condensed, JetBrains Mono) #503

The site generator ships third-party webfonts without their licence text.

What

• scripts/site/fonts/inter-*.woff2 (Inter)
• scripts/site/fonts/barlow-condensed-*.woff2 (Barlow Condensed)
• scripts/site/fonts/jetbrains-mono-regular.woff2 (JetBrains Mono)

All three are SIL Open Font License 1.1 families; OFL requires the licence text to travel with the font files, and the repo's own CC BY-NC-ND licence cannot apply to them.

Suggested fix: add one OFL text per family under scripts/site/fonts/ and have the site build copy them next to the published fonts.

Where it is catalogued: site-webfonts