The offer is the legal document a purchase accepts, needed before real-money
intake goes live. Convert the source PDF to an editable ui/legal/offer_ru.md and
render it to a standalone static dist/offer/index.html at build (a vite
emit-offer plugin using marked); the landing container serves it at /offer/,
with a bare /offer redirecting in. Add a small centered "Публичная оферта"
footer link on the landing (ru/en) and a CI probe asserting /offer/ serves the
page rather than silently falling through to the landing shell.