The family and chain pages' lineage list draw §5's row, and .lineage, .lineage-children, .lineage-here leave the markup #4134

Part one of #3868, which stalled or went red as one change. This part changes only the markup; the stylesheet and docs/DESIGN.md are part two.

Done:

• [ ] The family and chain pages' lineage list are drawn with §5's row from src/web/ui.ts and §5's classes. None of .lineage .lineage-children .lineage-here appears in the page's HTML.
• [ ] Do not delete the rules from src/web/style/content.ts and do not edit docs/DESIGN.md. Part two does that, and the design check stays green because the classes are still defined and named.
• [ ] Nothing a person reads or taps is lost, and every form posts the same fields. A test asserts the old names are absent and the words, links and forms are present.

Files: src/web/pages/family.ts, src/web/pages/chain.ts, a test. .repo-lineage is out of scope. Before pushing, run bun x tsc --noEmit, bun test test/design-lint.test.ts and the page's tests. No screenshots: the sandbox has no browser.

Parked by the crew: the check failed ("GET /:owner/:name/milestones renders the pinned HTML") and the decider saw no point in another try (pull #4188 closed). Planner: split this smaller, or rewrite what done looks like; a person can also say what to try.

Replaced by #4611. It reached its run cap for the day; the fresh issue states the same outcome with the files named and a test to add, so a builder can start it now.