Control and subscribe to SmartThings devices and scenes using the SmartThings REST API

Steps

1. Create a Personal Access Token (PAT) at developer.smartthings.com with the required scopes (r:devices:*, x:devices:*, r:scenes:*, x:scenes:*); include the token as Authorization: Bearer <PAT> on all requests to https://api.smartthings.com/v1
2. List devices with GET /v1/devices; each device object includes deviceId, name, and a components array; retrieve current status with GET /v1/devices/<deviceId>/status to see all component and capability values
3. Send a command with POST /v1/devices/<deviceId>/commands with body {"commands":[{"component":"main","capability":"switch","command":"on","arguments":[]}]}; check the capability name and supported commands from the device's presentation
4. List scenes with GET /v1/scenes?locationId=<locationId> and execute a scene with POST /v1/scenes/<sceneId>/execute; scenes set multiple devices to target states atomically
5. Create a SmartApp webhook subscription to receive real-time device events: register a publicly accessible HTTPS endpoint, implement the CONFIRMATION lifecycle to echo the challenge, and handle the EVENT lifecycle to process device state changes
6. For subscriptions, POST /v1/installedapps/<installedAppId>/subscriptions with {"sourceType":"CAPABILITY","capability":{"locationId":"<id>","capability":"switch","subscriptionName":"switchSub"}} to subscribe to capability events