Internal parts are no longer built inside each other

Everything in the mesh runs on a small internal component that is created on demand. Two of those components were doing part of their setup during their own construction — and that setup created further components, which created further ones again.

Nothing failed visibly, but it made shutdown harder than it needed to be: stopping something while it was being created meant racing a whole tree of half-built parts rather than a single one, and that race is the shape behind a long line of shutdown bugs.

The setup now runs immediately after construction instead of inside it. Nothing about the order in which your pages, data and code cells become ready changes — the component still finishes its setup before it accepts any work.