vm01 gains a primary IPv6 next to its IPv4, one standalone IPv6 address
joins the dataset; covers ip_version on both sources, combination with
filters, the IPv6-preferring behaviour of netbox's combined primary IP,
and the invalid value error path.
seed.py populates the stack through the API: a read-only user with a
self-provisioned token, tenants, sites, clusters, a VRF, virtual
machines (one with a primary IP) and standalone addresses; the tests
run the real inventory script against every source/filter combination,
every error path and the ansible --list/--host protocol.
