>> The house has the power to hold her in contempt and to send their own marshals to have her arrested and brought in for confinement.
Absolutely correct!
Absolutely correct!
Except it hasn't been done since 1934. For good reason.
I believe the arrest authority of the Sergeant at Arms is now restricted to Capitol Hill, period. And the Congressional jail is merely a temporary holding tank for any rowdy demonstrators -- and isn't equipped to feed or handle overnight guests.
Accordingly, while Congress might have the authority to arrest and confine people under an "inherent contempt" charge, they no longer have the ability to do so (nor the will, evidently).
Don't shoot the messenger...