Stop grouping transition nodes by label.
This was fine for mermaid rendering in API, but this UI now shows
notifications & permissions, which can be unique per transition.
Previously pre-grouped transitions hid actual permissions/notifiers of other transitions with the same label & to state.
Reimplement controls with MUI
It looks nicer & more consistent
Add control to reset persisted layout to auto generated one.
If the workflow changes enough (like with bullet point # 1), users may want to start over.
This gives the option without having to "clear everything for site data".