FX.14 Student Program: applications stay out of the inbox; every program email shows its Brevo status

When the verify step was added, StudentProgram::apply still created a normal Contact message, so each application landed in /admin/messages, mailed staff and sent an acknowledgement next to the verify email. Now the form's words are kept as an archived message (Contact::submit ctx quiet), with no staff note and no acknowledgement. /admin/students has a Last email column and a notice for verify emails that did not get through; /admin/student has an Emails section (status, opened, clicked, the refusal reason), from email_log. The resend message says the email was handed to Brevo, not that it was sent. Found through a school (itcgalilei.edu.it) whose mail server refuses our mail with 550 5.7.1; that applicant cannot verify at that address. Tested with bin/test-student-program.php (91 pass) and by rendering the pages on real rows; no new application has gone through the live form since.