Discover Shelly devices by probing HTTP endpoints on a subnet.
If no subnet is provided, attempts to detect the local network.
This method is slower than mDNS or CoIoT but works when multicast
is blocked or devices are on different VLANs.
The scan probes each IP address in the subnet range for Shelly device
HTTP endpoints. Progress is shown in real-time. Discovered devices
can be automatically registered with –register.
Use –skip-existing (enabled by default) to avoid re-registering
devices that are already in your registry.
Output is formatted as a table showing: ID, Address, Model, Generation,
Protocol, and Auth status.