New global mail/ module mirroring the files/storage/ provider pattern:
- MailProvider abstraction; default LogMailProvider only logs (no delivery),
MAIL_PROVIDER=smtp switches to a nodemailer SMTP transport (SMTP_*,
MAIL_FROM).
- MailService.sendTeamerInvite() composes the invite email with a link
built from APP_BASE_URL.
TeamerService.createInvite() now mails personal invites (those with an
email) best-effort and returns `emailSent`; group links are unchanged.
Delivery failures are logged and swallowed, never blocking invite creation.
New env: APP_BASE_URL, MAIL_PROVIDER, MAIL_FROM, SMTP_HOST/PORT/SECURE/
USER/PASS. Tests: teamer spec covers mail-on-personal-invite,
no-mail-on-group-link, and transport-drop; npm test green at 56. Docs
updated.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
