Add email to your app with one prompt

Set up Groundmail (transactional email) in this project. Do the work yourself.
Ask me before anything that emails anyone except me, changes DNS, or touches billing.

## 1. Install and sign in
```bash
npm install -g groundmail-cli   # or put `npx -y groundmail-cli` in place of `groundmail` below
groundmail login
```
`login` opens my browser: tell me to sign up if I don't have an account yet, then click Approve. Then run `groundmail whoami`: it shows my account email, used below.
No API key is needed for this: the sign-in covers every `groundmail` command. (In CI, `GROUNDMAIL_API_KEY` is used instead.)

## 2. Prove it works (sandbox, no domain needed)
```bash
groundmail emails send --from noreply@mail.groundmail.dev --to <my account email> \
  --subject "Groundmail works" --html "<p>It works.</p>"
```
You get an id like `msg_…`; confirm delivery with `groundmail emails get --id <id>`.

## 3. Sending domain (ask me which domain first)
```bash
groundmail domains add <domain>
groundmail domains apply <domain> --provider cloudflare   # or vercel / godaddy
groundmail domains verify <domain>
```
If my DNS is somewhere else, show me the records from `groundmail domains get <domain>` to add. DNS can take a few minutes; re-run verify until it says verified.

## 4. Wire it into the app
- Make a send-only key for the app:
  `groundmail keys create --name "<app> production" --scopes emails:send`
- Save it as `GROUNDMAIL_API_KEY` wherever this project keeps secrets. Server-side only; never commit it or expose it to the browser.
- Install the SDK (`npm install groundmail`; Python, PHP, Ruby and Go SDKs exist too) and add one send helper that follows this project’s patterns. The API base URL is https://api.groundmail.dev.
- Use it for the first real flow I name (password reset, receipt, …).
- Give every send an `Idempotency-Key` header (SDK option `idempotencyKey`) unique to the message, and reuse it on retries.
- On an error, branch on `error.code` and follow `error.hint`. Retry only 429, 500, 502 and 503, with backoff and the same Idempotency-Key.
- Prefer the canonical field names (`html`, `text`, `reply_to`).

## 5. Before real traffic
The free plan only sends to my account email until a domain is verified and a payment method is on file (no charge until an upgrade). If I need to add one, send me to https://app.groundmail.dev/settings/billing.

## Done when
- The test email arrived at my account email.
- The domain is verified.
- One real flow in the app sends through Groundmail.

## Reference
- Optional Agent Skills: `npx skills add Groundmail/groundmail-skills --skill groundmail -y` (https://docs.groundmail.dev/ai/agent-skills)
- Agent notes: https://docs.groundmail.dev/ai/agent-skill
- Quickstart: https://docs.groundmail.dev/quickstart
- Errors: https://docs.groundmail.dev/errors
- llms.txt: https://docs.groundmail.dev/llms.txt
- OpenAPI: https://docs.groundmail.dev/openapi.yaml
- Dashboard: https://app.groundmail.dev