Revoke a public link

Internal pages (every space by default) can only be shared by the space owner or a workspace owner/admin, with confirmInternal=true; every link expires. The public read and save re-check revocation, expiry, trash and, for internal pages, the approval on every request, and answer 404 for a dead link. Anonymous edit links are turned off unless the deployment sets NOTES_ALLOW_EDIT_LINKS=true: mode=edit is refused with 403 edit_links_disabled, and existing edit links serve as view links (the public read reports mode=view and the public save returns 403).