The business profile already carried the operator's full issuer block —
address, phone, email, website, VAT id — but none of it reached an email.
Those columns only fed the quote/invoice PDF renderer, so every outgoing
mail footer was the fixed logo + company name + copyright line.
The signature is rendered by wrapEmailHtml and nowhere else, so no
template, no per-type send path and no queue row needed a change. Two new
columns on business_profile (migration 198) carry the toggle and one
free-text legal line; everything else is read from the address fields the
operator already maintains.
Default off, with a test pinning that the disabled path is byte-identical
to a no-profile install.
Includes three rounds of external review fixes: the plain-text MIME part
also carries the signature; string booleans ('false'/'0') no longer
invert the toggle; the status line stays silent rather than asserting
"off" while unauthorised or loading; and the preview's Text tab mirrors
the send path's htmlToText fallback.
Manual Messages replies deliberately keep no signature — they bypass the
wrapper by design — and the UI copy names that exception.
Closes#1264 (Part A)
Paul Nothaft