feat(colophon): add a Ko-fi link, and group the author's links together

The link sits last in the existing row beside @StereotypicalCat and Source
code, in that row's own muted grey, with the same hover and the same small
mark. No accent colour, no button, no sentence asking for anything, and the
footer still contains no appeal anywhere — a test asserts that. This page earns
its keep by being trusted about dates, and a tip jar competing with the
disclaimer two paragraphs above spends that trust to make an ask. As one more
link it costs nothing and is there for a reader already looking.

The row also moves above "Additional ideas and design from". That row is who
built this and where to find them; the credit below it is other people. Reading
order now follows that split, instead of routing a reader past five strangers'
handles to reach the author's own links.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

AGENTS.md

@@ -119,7 +119,7 @@ src/client/       React app, service worker, manifest
                   theme.ts — dark or light, and what a game hue reads as on each
 scripts/          build-feed.ts, build-static.ts, parse-fixture.ts (offline), refresh-sources.ts (fetches)
 serve.ts          static server + /api/health
-test/             730 tests
+test/             732 tests
 fixtures/<game>/  raw HTML + .expected.json per source — pinned, kept forever
 snapshots/        current page per source, rewritten by refresh — see its README
 ```