`generate-skill-docs.py` now deletes every page under `user-guide/skills/{bundled,optional}`
it did not write this run, together with the zh-Hans mirror twin, so a skill that moves,
merges or leaves the shipped set takes its page with it instead of lingering as an orphan
that cross-links still reach (24 such pages after the shipped-set slim, plus 21 zh-Hans
copies whose English page was already gone).
The Docs Site Checks workflow regenerated the docs and never compared the result with the
committed copies, which is what GitHub renders; it now fails with a pointer to the generator
when they differ. Also regenerates the two pages that drifted since the salvaged commits.
1536e75bfe