Switch out maverick-js/signals for @webreflection/signals

see https://github.com/WebReflection/signals – bundle size is supposed to be 0.5kb (vs 1kb for maverick)

https://github.com/tc39/proposal-signals doesn't seem to be moving forward, so...

Locate where maverick-js/signals is declared and used, then read the @webreflection/signals project linked in the issue to compare its integration requirements. The work is done when the dependency has been switched without breaking the library and the resulting bundle size can be checked against the stated goal.

Written by the indexing model from the issue text.