The heatmap now counts "updates", not "releases". Each CHANGELOG.md entry is one
shipped change (tagged Added/Changed/Fixed), not a versioned release — so a busy day was
misreported as "19 releases". The count language across the heatmap summary, day tooltip,
and panel now reads "N updates" (GitHub's honest "contributions" framing). The page and
nav stay named Releases — that's the section, like GitHub's Releases tab.
The day-summary list is redesigned. The former wall of plain blue links is now a
structured list: each update is a row with its title (left, aligned) and colour-coded
change-type tags (Added / Changed / Fixed / Removed / Security) on the right, with
hairline dividers; busy days scroll within the panel. "View details" now reveals each
update's one-line summary in place instead of swapping to a separate layout.
lib/changelog.ts: new changeKinds(body) derives the tags from an entry's
### … sub-headings (canonical order, splits "Added / Changed", ignores prose
sections like Notes/Verified). Tag colours reuse the --st-ok/info/warn/bad tokens.
