LXCGetIPsWithStatus reads net config for stopped and suspended guests instead
of the interfaces API. UpdateResources reuses IP lists for 30s when the
resource status is unchanged, caps concurrent LXC IP lookups, and sets
MaxConnsPerHost on the HTTP transport to match.
Add httptest coverage for offline IPs, second-poll IP reuse, and status
transitions. Replace math.Pow session backoff with fixed-duration retries.
e1eb8e9c03