If I understand what has happened, the tapered stem retaining nut is at the bottom of the fork tube. Just loosening the stem bolt, there is no room for the nut to go lower? Because if this is the case, you need to move the fork away from the stem. Easy way could be with a helper. With the stem bolt loose, have the helper hold the bike in the air with the handle bars. With a rubber mallet, hit the main frame, near the head tube down.I think I tapped it in an inch too far. I don't see any way of pulling it back out. Anyone done that?
Without a helper, maybe position the handle bars on 2 chair backs to keep the front in the air. Then knock the frame down.