The repository's audience mark draws §5's badge, and .repo-audience leaves the stylesheet, its test updated with it #4889

Intent: #4589 rewritten. Its pull #4627 stayed red. test/repo-audience.test.ts and test/audience-surfaces.test.ts assert the old class, so they must change in the same pull.

Done:

• [ ] src/web/chrome.ts (the two repo-audience lines in the audience mark) draws a §5 badge() with the audience word, keeping the admin's link to settings and its title sentence
• [ ] .repo-audience and a.repo-audience:hover leave src/web/style/content.ts, and its §5d line goes
• [ ] test/repo-audience.test.ts and test/audience-surfaces.test.ts assert the badge and the word, not the class; a look at 375 px shows the mark does not push the title off a line

Files: src/web/chrome.ts, src/web/style/content.ts, docs/DESIGN.md, those two tests.

Run bun scripts/design-lint.ts and bun test test/design-lint.test.ts before pushing; lower docs/design/baseline.json only where a count fell. In docs/DESIGN.md, delete only your classes' own lines from §5d (one class per line since the issue this waits for), so parallel pulls do not conflict. If a test you did not touch goes red, name it in the pull and do not fix it here.