On exit 3010 the old path issued Restart-Computer, slept 30s, then probed
WinRM. With a pending WU/CBS install the restart is delayed minutes while
the WinRM session stays alive, so the probe saw the still-up pre-reboot
session as "ready" and re-ran the toolchain — which then died mid-run when
the real reboot kicked in (looping "treating as 3010").
Add `_reboot_and_wait`: issue the reboot, then wait for TCP/5986 to go
*down* (`_wait_tcp_down`, up to 300s) before waiting for it to come back
and re-probing WinRM. Use it for both the 3010 loop and the final reboot.