feat(podcast): the real Show Your Work cover art

[schmug]

This replaces the Show Your Work placeholder cover with the real show art (clodcast plan Task 11, schmug/clodcast#238).

• public/show-your-work-cover.jpg is now a byte-for-byte copy (sha256 prefix def1e4a026e11c1e) of clodcast's skills/show-your-work/refs/cover.jpg: 3000×3000 RGB JPEG, 429 KB. Cory approved it on 2026-09-26. Its source and generator land in feat(syw): show cover art clodcast#247. COVER_URL is unchanged, so this is a file swap at the same path.
• scripts/generate-show-your-work-cover.mjs is removed. It only cut the placeholder, and keeping it would let someone re-cut the placeholder over the real art.
• The comment in src/pages/show-your-work/rss.xml.ts and the COVER_URL row in docs/podcast-metadata.md now point at the clodcast source.

Local gates:

$ npm run format:check   ->  All matched files use Prettier code style!
$ npm run lint           ->  exit 0
$ npm run typecheck      ->  0 errors, 0 warnings, 1 hint
$ npm test               ->  Test Files 38 passed (38), Tests 369 passed (369)
$ npm run build          ->  30 page(s) built, dist/show-your-work-cover.jpg 428958 bytes

npm run test:e2e was not run locally (it needs Playwright browsers). Its cover check asserts a 200 response and an image/jpeg content type, which the swap preserves; CI runs it.

Merging deploys the site. Nothing else changes, because the show page stays in its empty state until episode one publishes.

🤖 Generated with Claude Code