Issue C3 — Centre block on the guide

Summary

One section on /guide. No careers page. Add it with #208 to #214.

Copy

• A partner centre can ask us to introduce a tutor for one student.
• The fee is shown to the payer first. We do not post jobs.
• A public advert is not available.

Acceptance

• /how-it-works has no “hire tutors” button.
• The section links to centre-2026-10.