fix(lume): run macos installer on vm queue

[injaneity]

what changed

DarwinVirtualizationService.installMacOS now captures its VirtualMachineHandle and dispatches installer construction, progress-observer registration, and install through the virtual machine's private queue. The progress observer stays alive until the install completion callback.

why

Issue #2670 reports a dispatch_assert_queue trap in VZMacOSInstaller.init. The virtual machine is created with a private serial queue, but the installer was created in an unqualified Task on the service's main actor. Virtualization requires installer setup on the virtual machine's queue.

impact

lume create no longer constructs VZMacOSInstaller on the wrong queue after an IPSW download or local IPSW selection.

validation

• swift test --package-path libs/lume --filter VMVirtualizationServiceTests
• result: build succeeded; 6 tests passed
• git diff --check

A live IPSW install was not run because this checkout has no prepared restore-image integration fixture. The package compile verifies the Swift 6 concurrency boundary, and the source change directly matches the framework queue assertion.

[f-trycua]

Reviewed at bc7b342. The installer is now created and started on the VZVirtualMachine serial queue, matching Apple’s queue contract and the surrounding service pattern. Focused tests and all required checks pass.