Review findings on the caching commit:
- ~/.cache/electron was dead weight: with npm ci skipped on an exact
cache hit, the download cache is never read (electron's unpacked
binary lives in node_modules/electron/dist, inside the cached tree);
it only inflated every saved archive by ~110MB.
- 'npm i -g npm@12' ran unconditionally in all 14 matrix jobs
(~5-15s each); now a no-op when the bundled npm is already 12.x,
which also keeps the installed major aligned with the npm12
cache-key tag.
yaml + actionlint pass.
de0abc0617