Am I allowed to publish games I made with quest5 on platforms like Steam or GOG?

Sure. You will probably need to convert them to JavaScript though - you can do that using http://questjs.textadventures.co.uk/

When did that appear?

It's been around for a while: viewtopic.php?f=10&t=4451 - in fact, you've even posted to that thread...

Lol. I didn't realise there was an online compiler - I thought it was something in github. Or maybe the alzheimer's has finally kicked in.

ah, awesome, thanks a lot!