Decide and scope post-auth email notifications

[Taleef7]

Context

docs/GAP_ANALYSIS.md accepts no email notifications beyond Supabase Auth for MVP, while docs/MVP.md marks transactional email as optional.

Acceptance criteria

• Decide whether MVP 0.2 includes automated email notifications for payment received, tutor assigned, schedule changes, or renewal reminders.
• If in scope, choose provider and define templates/events.
• If deferred, document WhatsApp-only communication as intentional for the release.
• Create implementation issues if email is approved.

References

• docs/GAP_ANALYSIS.md D2
• docs/plan-CorvEd.md open question T0.1 finalize MVP rules in docs/PRODUCT.md #2
• docs/MVP.md section 8.4