Nice, I like how you start out with the finite dimensional case here. Personally though, I don't think I really "got" quantum mechanics until I saw Bell's inequality, so I prefer to put that front and center.

Maybe a pointless nitpick, but is a PDF on GitHub really the best way to distribute this though? I guess you also didn't want to give away the .tex file? arXiv is usually the best place to upload these kinds of notes so they can be indexed and easily found.

This is fantastic, although the statement about the intended audience cracked me up a bit: "intended for a general audience including ... anyone interested in a concise intro/overview of QM. Prerequisites: linear algebra, calculus, ..."

The PDF is essentially higher math with QM-related narrative interspersed here and there. Even if you're a STEM graduate, I found that these skills atrophy pretty quickly if you're not using them day-to-day in your work. Scientists often vastly overestimate how conversant their readers are with "obvious" prerequisites such as vector calculus.

And you can often tell on HN, because you have a thread where two mathematicians chat with each other, and then everyone else is just relating anecdotes about quantum mechanics.