fwiw there are plenty of webserver cli's with reload capability (https://www.npmjs.com/package/live-server or npx serve + chokidar), this is definitely one of those things that can decomposed to single responsibility tools

(nit: hot reload means a specific thing in the js ecosystem and you prob dont mean that)

Sure, but using Node would mean losing the advantage of this being a single static binary. Not everyone has Node installed already.