chore(seo): refresh the stale dateModified on /api/

`src/org/api/index.md` has been claiming 18:31:40 since Wave 1, because
pageDates.json was last regenerated in bce51a7 (19:04) and Wave 2's fa0aecb
edited the page at 21:35. Two waves of lag, reported by check:dates on every run
since — which is how a warning stops being read.

gen-page-dates deliberately treats `modified` drift as non-fatal ("a dateModified
that lags by a few commits is honest"), and that stays true. This is just the
chore it declines to force.

Worth recording that it cannot fix the general case, though: the /api/ landing
page is data-driven from api-packages.js, so shipping a package changes what the
page renders — Wave 4 added a whole "Background work" group to it — without
touching the file git derives the date from. So a data-driven page's dateModified
under-reports by construction, and no amount of regenerating changes that.

Author: Mikhus

src/_data/pageDates.json

@@ -29,7 +29,7 @@
   },
   "src/org/api/index.md": {
     "published": "2026-07-19T22:58:50+02:00",
-    "modified": "2026-07-31T18:31:40+02:00"
+    "modified": "2026-07-31T21:35:26+02:00"
   },
   "src/org/blog/authors.html": {
     "published": "2026-07-22T04:09:43+02:00",