Email/signature: expand the available sender variables (mobile phone, job title and more)

Jira: TN-8697 - [Email] [Quote] Add mobile phone as template variable.

Expand the set of sender/user variables available in email and signature templates. The original ask is a mobile phone variable; a second tenant (Belton IT Nexus) asks to broaden this to more sender fields such as job title and other sender details, so signatures can be built fully from variables. Keep this card as the single place to collect which sender fields people need.

Keywords

email signature variable, sender variable, template variable, mobile phone variable, merge field, job title variable