Behind -tags=integration and self-skipping unless KVM_TEST_* names a
host: one sequential lifecycle (image fetch, Create, idempotent
re-Create, Running with IP, ListByTag, Delete, pool state afterwards),
driven through the provider directly so it needs no Step 5 wiring.
Adds `make test-integration-kvm` and documents the run and the
deviation from the testcontainers convention in docs/testing.md.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>