Would you consider renaming the note to contain a reference to the generated code? Such as "Thoughts on Hedgehogs.md" becomes "Thoughts on Hedgehogs [AB-99].md"

This preserves your goal of having the system rightfully not need another source of truth outside the markdown files, but also lets the markdown file carry the identifier across renames without adding a YAML block.

And it lets you find the note in the "open note" dialog box by typing the code, so no other kind of search interface is needed. Or even to find the note with any other filesystem utility if you have your reference code.

Were you inspired by the Zettelkasten Method for your plugin?

Hmm... Not a fan of that approach. Would mess things up for my personal use case, at least, making the names less nice. I'm leaning on having some sort of a vault-specific database tracking existing codes across renames as an addition to the existing mechanism. I actually do like the idea of adding tags in the frontmatter, but then it'd become impossible to tag files and folders.

If only we had resource forks.

As for inspiration, I'm not really much of a note-taking system person. My system is just hyperlinking lots of notes together: https://ezhik.jp/hypertext-maximalism/ - this little plugin just helps with that outside of my vault.