Email never reports "Sent" without sending

If a portal was switched on for e-mail but had no mail sender installed, outbound messages and invitations were marked Sent while nothing actually left the portal. Nothing looked wrong: the message record said delivered, and no error appeared anywhere. The only way to find out was that the mail never arrived.

That can no longer happen. On a portal in that state, e-mail now stops instead of pretending: the message stays visibly queued, the failure is reported, and the cause is named. Once the mail sender is installed, the queued messages go out on their own — nothing needs to be re-created or re-sent by hand.

Portals that send mail normally, and portals with e-mail switched off, are unaffected.