Mirrors the Payload backend's new company-settings.legalForm field: when
present, registerCourt/registerNumber/managingDirector now appear in the
email footer (buildLegalFooterLines) and both invoice PDF footers,
matching §37a HGB / §35a GmbHG requirements for registered legal forms.
A sole proprietorship (the default) renders identically to before —
these fields are only appended when actually set.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
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.