One change rebuilds a type once, not several times

A single change — saving an edit, pushing, installing a package — could rebuild the same type several times in a row. Each rebuild interrupted whatever was open: pages built from that type reloaded, and the "a newer build is available" prompt appeared again and again. A slide deck being presented could rebuild while it was on screen.

Repeat rebuilds that would produce exactly the same result are now recognised as such and skipped. If the content really has changed in between, it still rebuilds — and asking for a rebuild explicitly always does one.