Glad you're OK.
IMO, pointing out how vulnerable we all are is NOT helpful, nor is ranting against cagers, pedestrians, etc!! Encouraging us to wear all the gear all the time is only slightly better.
LEARNING what happened and PRACTICING to avoid it is the real ticket to not having it happen again.
I agree with Gaither as to what happened, although I suspect the front wheel skated out on you on the compression rather than the rebound. Circumstances are nearly the same, though. Slow speed, wheel slightly turned, sudden application of the brake. Won't take much brake, either, with the wheel turned but no spinning gyroscopic wheel to keep things inertially upright. And yeah, the paint etc could very easily be a contributor. It would be very worthwhile on your next trip through that intersection to try and reconstruct exactly where you were and what other contributors there may have been.
The thing to practice is that 'reflex' hard squeeze on the brake. Now, don't get me wrong, I'm not dissin' you, but I'm betting that if that reflex squeeze had been 'practiced out' of you, a controlled stop would've kept you upright and still missed the stopping truck.
A very similar reflex action is stomping on the rear brake, sending the rear end off on it's merry own way. This happened to me in almost exactly the same situation: left turning, stupid oncoming driver changing up at the last minute, truck in front of me stopping to miss stupid oncoming driver, me 'reflex' stomping on the rear brake, locking the rear wheel and sending it sideways. Luckily for me, I eventually stopped before hitting the truck and the rear didn't step all the way out leading to a low side. But again, it was the 'reflex' stomp that did me in.
AFAIK, the only way to 'practice' that out is to practice full-on hard instantaneous braking out in the boonies or in a deserted lot or whatever. Over and over and over and get the feel for exactly how much strength is required, and get a feel for what your 'grip' feels like when applying how much braking. Get your hand/wrist/arm/brain "used to" what all that feels like. Get an idea of how this particular bike behaves under all this.
And of course, watch out for idiots and wear your gear...
Kirk