0954ad4b9b
npm runs the `postbuild` hook after every `npm run build`, and the desktop compiler (scripts/build/desktop.mjs) already runs checkDistBuilt on the scratch product before it publishes dist/. Every update and every pack therefore re-verified the bytes it had just verified; with the per-chunk syntax check that was a second ~960-process pass (#123216). Drop the hook; nix's checkPhase calls the guard directly.