a40b8217b3
Apply the <10-LoC / <3-non-test-caller heuristic across the package: inline writeControlFrame, removeLeaseWaiter, vhciAttach, vhciHubForSpeed, applyControlSnapshot, applyRemoteEntries, shouldRetryBusID, entrySerial, and the trivial darwin/linux import-host constructors at their call sites. Delete the darwinClientSession wrapper -- darwinVirtualController already satisfies DataSession, so attach the Description() method to it directly and return the controller from darwinImportHost.Attach. Fold the 11-line data_session.go into host.go beside AttachedSession, which embeds DataSession.