Implement human-in-the-loop approval in a Trigger.dev v4 task using a wait token completed by an external system

Documented steps

1. Import `wait` from `@trigger.dev/sdk` (https://trigger.dev/docs/wait-for-token).
2. Inside the task create a token: `const token = await wait.createToken({ timeout: "10m", tags: ["approval"] });` — the default timeout is 10 minutes.
3. Send `token.id` (or the browser-safe `token.publicAccessToken`, or the provided callback `url`) to whoever must approve — email, Slack, or your own UI.
4. Block the run on the token with a typed result: `const result = await wait.forToken<ApprovalToken>(token.id); if (result.ok) { /* result.output */ } else { /* timed out */ }`, or use `.unwrap()`.
5. Complete it from your backend: `await wait.completeToken<ApprovalToken>(tokenId, { status: "approved" })`, or over HTTP `POST https://api.trigger.dev/api/v1/waitpoints/tokens/{tokenId}/complete` with `Authorization: Bearer <secret key or publicAccessToken>` and body `{ "data": { ... } }` (https://trigger.dev/docs/management/waitpoints/complete).
6. From a browser, complete the token with only the `publicAccessToken` — that endpoint is CORS-enabled for exactly this case; never ship the secret key to a client.
7. Guard against duplicate tokens on task retries by passing `idempotencyKey` and `idempotencyKeyTTL` to `wait.createToken()`.