Withings OAuth endpoint

Status: configured

• GET /withings/start — begin the OAuth2 flow
• GET /withings/callback — redirect URI registered with Withings
• ANY /withings/notify — data notification webhook
• GET /withings/token?userid=… — current access token (admin)
• GET /withings/users — linked accounts (admin)
• GET|POST /withings/subscriptions?userid=… — notification subscriptions (admin)
• GET /admin — credentials and subscriptions UI, behind Cloudflare Access

Redirect URI in use: https://health.payitonchain.com/withings/callback