How do you get burned wood off of a glass stovetop?

Some people might be inclined to think your glass is damaged rather than dirty, and that's why you can't get it clean. In a comment you say that the discoloration is raised, which suggests that's not the case. However cook tops are, by definition, heat resistant, and I'm also assuming you didn't let this fire rage out of control for an extended period of time. I believe you're correct and the glass is fine, just dirty.

You've mostly done what I would try except I would use a scrubber sponge designed for glass cook tops. Get a fresh one, spritz it with a bit of water (it seems to scrub less well if it's too wet or completely dry), apply a generous amount of cleaner and start scrubbing with as much force as you can muster. If your sponge turns black or grey then you know it is working, even if it's slow. Move to a new spot on the sponge if it gets dirty enough that it's not rough to the touch anymore. You may have to scrub a lot. You could also try a different brand of cleaner, some do work better than others.

You could also try a razor blade, unless that's what you mean by "scraper tool". This is a pretty common method of getting burnt-on stuff off of glass cook tops, though I've never personally had to resort to it. If there's a lot of gunk, it may save you some scrubbing.

I tried looking for solvents that are safe to use, but wasn't able to find any. I even found a note that you shouldn't use regular glass cleaner because the ammonia in it isn't good for glass cook tops. I'm not sure if that's true, but you might want to avoid trying that again. It's only good for smudges anyway, so there's no reason to risk it.

My only other thought is to try soaking a towel in hot water and putting that on the gunk for a bit before scrubbing, as maybe that will soften it up. Wipe up excess water before scrubbing so the abrasives in the cleaner can do their work instead of just swimming in water.

Good luck! If you do solve it, please report back what worked best.

I have had great results using a single-edge razor blade to clean discolorations from my glass cook top. I am religious about keeping my surfaces clean, but sometimes heat and "some unseen agent" form a discoloration that routine cleaning won't remove. Razor blade to the rescue!