Mark A,B,C,E,D-intro,F,G,H approved with verbatim text; redraft D
(no Octave One, live-hardware spirit) pending approval; resolve the
medium-card question; flag two COPY C typos for confirmation.
Three-movement About page (People/Process/Product) in the Home page's
existing visual language; draft copy fenced for approval, image slots and
open questions captured. Adds product-notes/about-page.md and PLAN.md §12.