Coming back to this a few days later... it looks like the fastest way to implement this idea is to host a local TiddlyWiki instance. There are so many TiddlyWiki plugins that fit so naturally into the ideas I had above -- kanban, todo, and the wiki itself, among many others.
The next evolution would be to get it running in RedBean reliably - and maybe even get it saving Tiddlers to the built-in SQLite instance. Simon Willison's work on saving Tiddlers to SQLite in Python might be a good reference: https://github.com/simonw/datasette-tiddlywiki
I tried this Ruby script for local hosting and it's working great for now: https://gist.github.com/jimfoltz/ee791c1bdd30ce137bc23cce826.... Just make sure you have wiki.html located alongside the script, and navigate to /wiki.html.
The next evolution would be to get it running in RedBean reliably - and maybe even get it saving Tiddlers to the built-in SQLite instance. Simon Willison's work on saving Tiddlers to SQLite in Python might be a good reference: https://github.com/simonw/datasette-tiddlywiki