Well, I guess I sort of fixed it.
I went and bought a can of silicone spray lube.
Sprayed it as much as possible on that little bolt/stub that pops out to lock the steering head. And then I sprayed into the ignition too, and also I worked the in and out function of the key switch back and forth several times.
But! the forks still didn't want to turn easily. Finally I sat on the bike and just yanked them and with some kind of grinding noise I did NOT like, they went ahead and turned. So after waggling them back and forth a bunch of times, and spraying the lube around where the fork trees contact the fork stem, I got it pretty loosey-goosey. Like I wouldn't have noticed it, any drag or extra friction if I'd gone riding and it was like this.
So now the lock mechanism operates like it should. I ought to go out there and spray the gas tank lock too, cuz it is a pain in the butt sometimes.
I would go ahead and go riding, but the battery is still not at full charge. It does start right up now, but Batt Tender is still on "red", so I'll let it finish charging.
One odd thing I noticed in the service manual, while I was just looking in the index under "switches" - it refers to a kickstand (sidestand, jiffy-stand?) switch. I find that weird, since I've never noticed that having the stand up or down affects anything at all with regard to starting, etc.
I guess I need to see about getting the steering head really lubed/greased professionally. Or, maybe it's ok now, I dunno.
Another thing I'm suspicious about - the wire that comes out the back of the headlight - wow that thing has only a couple of hairs-width clearance to the front of the steering head. That could have prevented the forks from turning smoothly, but it does clear, just not by much. So I'm pretty sure that wasn't preventing the forks from turning.
I've had a bunch of bikes over the years. New bikes, old bikes - and none of them had forks that didn't want to turn easily/