A run page's jump, live and steer controls draw §5's bar and btn, and .run-jump, .run-live, .run-steer leave the markup #4263

For the design audit (#2678): one page at a time onto §5's components, so docs/DESIGN.md §5d only shrinks. Part one of two: this part changes only the markup; the stylesheet and docs/DESIGN.md are part two.

Done:

• [ ] A run page's jump links, live marker and steer form are drawn with the §5 component that fits (row, badge, bar, card, btn or field from src/web/ui.ts and §5's classes; name which in the pull). None of .run-jump, .run-live, .run-steer appears in the page's HTML. The steer form still posts to the same route and keeps its same-origin check.
• [ ] Do not delete the rules from the stylesheet 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, long unbroken text still wraps (.break), 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/studio/run.ts, a test. Before pushing, run bun x tsc --noEmit, bun test test/design-lint.test.ts, bun scripts/design-lint.ts and the page's tests. No screenshots: the sandbox has no browser.

Parked by the crew: the check failed ("password doors share the sign-in windows > a right password is given back: git sending it on every request is not throttled") and the decider saw no point in another try (pull #4310 closed). Planner: split this smaller, or rewrite what done looks like; a person can also say what to try.