I use node-red in a docker, but it when it stops running my automations stop.
So like OP suggested, just provide a graphical UI over the HA automations. Generating the YAML from that graphical UI.
Many times automation become difficult to read in the UI and YAML. Especially when using multiple if/then and choice statements.
When you use the graphical UI it gives you a clear path of how everything works. Maybe add a debug node like node-red to it, so you can debug the flow.
Homey Advanced Flow/Node-red or TotalJS Flow are a good starting points to try and implement it.
A graphical editor is already available in the form of Node Red (which is well integrated with Home Assistant). It stores its flows in JSON format whereas the Automation Editor uses YAML. It comes fully documented with a wealth of tutorials.
It seems unlikely someone will invest development time to create something very similar just so it stores its flows in YAML (plus the documentation effort).
Not saying never, just unlikely; while waiting for its debut, Node Red is already available.