Resolve the Root UI font leftover

src/styles/ids/settings.css declares @font-face "Root UI" from src/styles/ids/fonts/pt-root-ui_vf.woff2 and .woff, and both settings.css and ids.css:224 use it as the body typeface. PT Root UI is the Timestripe brand font.

At the same time static/fonts/ holds InterVariable.ttf and InterVariable.woff2, and nothing in src references them. Either the switch to Inter was started and never finished, or Inter was added by mistake.

Tasks

• Decide which typeface the bootstrap ships with: Root UI, Inter, or a system stack
• If Inter: point the @font-face at /fonts/InterVariable.woff2, update the two font-family usages, delete src/styles/ids/fonts/
• If Root UI: delete static/fonts/ and check the licence allows redistribution in a public template
• Drop the unused .ttf either way