Email notifications and transactional emails

[elias-ba]

Summary

Set up email delivery for invitations, notifications, and summaries.

Email Types

• Team invitation
• Estimation reminder (deadline approaching)
• Sprint summary (after completion)
• Disagreement notification
• Weekly digest (optional)

Email Provider Options

• SendGrid (generous free tier)
• Postmark (great deliverability)
• Mailgun
• Amazon SES (cheapest at scale)

Setup

```elixir

config/runtime.exs

config :estim, Estim.Mailer,
adapter: Swoosh.Adapters.Sendgrid,
api_key: System.get_env("SENDGRID_API_KEY")
```

Email Templates

• Use Phoenix templates or MJML
• Responsive design
• Plain text fallback
• Unsubscribe link

Acceptance Criteria

• Emails send reliably
• Templates look professional
• Unsubscribe works
• Email preferences configurable