feat(platform): add email delivery module, wire event bus into auth, update roadmap
- modules/delivery: 8 email templates, renderer, SendGrid/Postmark/console adapters, dispatcher, delivery log, 21 tests
- modules/delivery/subscribers: event bus listeners for user.created, password_reset, email_verified
- auth/routes: emit bus events on register, forgot-password, verify-email (fire-and-forget)
- cosmos-init: delivery_log container (pk /pk, 90d TTL)
- roadmap: updated inventory (30 modules, 14 packages, 988 tests), marked P0 items complete
- 988 platform-service + 14 events = 1002 total tests passing