Auto-email on status change (wire dormant cta path)

[hamin2006]

Context

Status changes made in the reviewer table or on the board are silent — no email fires when an applicant is moved to offered/rejected. The code was designed to support this (cta flag on updateSubmissionField) but no caller ever passes it, so the path is dead code.

Current behavior

• updateSubmissionField in src/app/portal/admin/actions.ts emails only when cta === true, then only { title, content } from the matched per-status template.
• No caller passes cta: in-cell updates (columns.tsx) and board drop-to-status (board/page.tsx) both call it without it. Emails are strictly manual via the per-row Notify button.
• Status history is recorded on every change regardless.
• There is no per-status "send email on transition?" toggle.

Desired behavior

• Optional auto-email when an application transitions to a status that has a saved email template, controlled per status (config flag, e.g. config.application.status[i].emailOnTransition, default off to preserve current behavior).
• Cell dropdown changes and board drag-drop both honor the flag.
• Opt-out escape hatch per application/row (e.g. do not email if an admin manually toggles, or "notify without email" action) so the flag never forces an email.
• Reuse existing renderStatusEmail template + tag rendering; failures toast without losing the status change.

Acceptance criteria

• Per-status emailOnTransition flag exists and is surfaced in the status/template settings UI
• Table and board transitions both trigger the email when enabled (and never send when disabled)
• Existing behavior unchanged for current forms (flag defaults off)
• Failure of the email send does not roll back the status change; error is surfaced