Fix 1 - UnPoller 404 on UDM Pro:
Remove :8443 from UP_UNIFI_DEFAULT_URL. UniFi OS devices (UDM Pro,
UDM, UXG, CloudKey) use a different API path and do NOT use port 8443.
URL should be https://10.42.1.1 (no port); unpoller handles the
/proxy/network path internally for UniFi OS devices.
Fix 2 - Grafana dashboards showing invalid datasource:
Add uid = "prometheus" to the provisioned Prometheus datasource.
Without an explicit UID, Grafana auto-generates one on first run.
All dashboard JSON references datasource uid "prometheus" which
only works if the provisioning explicitly sets that UID.