Bootstrap Postmark Mailer

Configure Postmark as the production email adapter for Swoosh in a Phoenix 1.8 app.

What Gets Configured

1. prod.exs — Swoosh API client set to Swoosh.ApiClient.Req, local storage disabled
2. runtime.exs — Postmark adapter with POSTMARK_API_KEY env var, configurable from address with MAILER_FROM_NAME and MAILER_FROM_EMAIL
3. config.exs — Default Swoosh.Adapters.Local for dev, default :mailer_from tuple
4. test.exs — Swoosh.Adapters.Test adapter, API client disabled
5. .env.sample — POSTMARK_API_KEY, MAILER_FROM_EMAIL, MAILER_FROM_NAME entries
6. Mailer module — Verified or created

App Name Detection

Detect from mix.exs:

• App module prefix (e.g., MyApp) — the module namespace
• OTP app name (e.g., :my_app) — used in config atoms
• Web module prefix (e.g., MyAppWeb) — for endpoint references