Unlike the email-templates preview (marketing copy), this page shows
real bank/address details once filled in — it must not render for an
unauthenticated visitor who finds the URL.
Company data now has its own Payload admin group and a live in-browser
PDF preview (react-pdf's PDFViewer) instead of just a plain settings
form. Invoice header is a brand-colored rule instead of a filled band,
and the footer is now pinned to the page bottom instead of following
content flow.
Marco