respect inclusions in star-invite-plus-star-subject

Ticket

+commit
 

In *invite+*subject and *signup+*subject, ideally you'd be able to put something like "Welcome to {{*title}}" so that when you change the title you don't have to change the +*subject cards as well.

 

 

 

this will be addressed implicitly when we convert system emails to flexmail system.  (closing)