What's the difference...

... between qi and ki?

Spelling.

IRL? literally just a different translation of a chines word. Its also spelled "chi" sometimes. In game, I wouldn't be surprised if its the same thing, different spellings of the same word. Or someone just forgot that they spelled it "Ki" in the monk stuff.

In game one uses focus points and is a Mechanic for monks and a dedication or two.

The other is flavor text basically.

Qi is worth more points in scrabble.

Chi uses the Ch letter in old spanish language rules.

Qi seems to be specifically an air-aspected energy of some kind based on the jiangshi's breath stealing referring to it.

But also there's so little information about both that it's Impossible to tell.