I just had a moment of realization, and took less than an hour to implement a fix for this website that has been bugging me for at least a year.
I now cache a hash of the file contents in the database, and when viewing a post, if the hash has changed, I rebuild the DB index. This saves me the step of going in and running the "rebuild index" command when I hand-edit files.
I'm about to live test a crazy new feature on my website, right as I'm getting on a plane for 10 hours with no internet. Hopefully I don't break my site with this! With any luck, in a few minutes, you'll be able to visit https://aaronparecki.com/checkins and see my flight status updating live! It should show a map with my plane's location, updating continuously for the next 10 hours.