Set up Grafana k6 synthetic monitoring checks via the Cloud API

Steps

1. Authenticate to the Grafana Cloud Synthetic Monitoring API using a Synthetic Monitoring token obtained from the SM plugin UI; pass it as Authorization: Bearer YOUR_TOKEN in all requests
2. POST to /api/v1/check to create a new check; specify job (name), target (URL or host), frequency (milliseconds between executions), timeout, probeIDs (probe location IDs), and settings (http, ping, dns, or tcp)
3. For an HTTP check populate the settings.http object with method, headers, and body; add validations such as failIfBodyMatchesRegexp or failIfStatusNot2xx to assert content correctness
4. GET /api/v1/probe to list available probe locations and their IDs; choose probes from multiple regions to get geographic coverage
5. Retrieve check results and uptime metrics from the Prometheus-compatible metrics endpoint exposed by the Synthetic Monitoring datasource in Grafana Cloud
6. Add alerting on the probe_success metric (value 0 means failure) using Grafana unified alerting rules targeting the SM datasource