3c6612a0

By: Michael Lynch <git@mtlynch.io>

$(cat <<'EOF'
Use email.SendFunc directly in loginmail.Sender

loginmail previously defined its own SendFunc type with unpacked
parameters, forcing session_options_prod.go to wrap email.SendFunc
into a lambda that repacked the same four fields. Now loginmail.New
accepts email.SendFunc directly, removing the wrapper and the
duplicate type.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
EOF
)