feat(emails): add remaining email templates

Commit notes

- Payment failed email for failed subscription charges - Subscription cancelled email with feature loss details - Payout emails (requested, completed, failed) for creators - Share link notification emails (access, download) - Password reset email with security details - Email verification email for new accounts

All templates use consistent EmailLayout and Tailwind styling.

Co-authored-by: armin.naimi <[email redacted]>