Support ticket email templates

Ticket opened/reply for user and staff. Staff mail goes to Contact email. Also gated by legacy ticket mail toggles.

Category label: Support tickets.

Key	When it sends
`support.ticket_created_user`	User: ticket opened
`support.ticket_created_admin`	Staff: ticket opened (`%ticket_message%`, `%admin_tickets_url%`)
`support.ticket_reply_user`	User: staff replied (`%ticket_url%`)
`support.ticket_reply_admin`	Staff: user replied

Common vars: %ticket_subject%, %ticket_id%, %username%, %site_name%.

Where to find it

Admin → Settings → Emails → Support tickets

Staff templates send to Contact email (Settings → Main). Empty contact = silent no-send.

Also gated by legacy toggles (empty = on): toggle.m_s_send_user, toggle.m_s_send_admin. Template Enabled must still be on.