Create a Home Assistant long-lived access token and use it to authenticate a script's REST API calls

Steps

1. In the Home Assistant user profile page, open the Security tab and select Long-Lived Access Tokens
2. Click Create Token, name it, and copy the token string immediately since it is only shown once
3. Store the token securely outside source control, since it cannot be retrieved again from the UI
4. Send it as an Authorization: Bearer <token> header on requests to Home Assistant's /api/ REST endpoints
5. Revoke the token from the same Security tab if it is ever compromised