Admin UI: show whether the engine runs the saved settings (F213 status field)

[genwave-radio]

🎛️ What

Show the F213 engine-settings verdict in the admin UI. /api/status already carries it:

"engine": { "settings": "inSync" | "restartNeeded" | "unknown", "differs": ["GW_XFADE_MIN", …] }

Right now it only shows up in jq and the api log (one WARN on entering restartNeeded).

✅ Wanted

• Plain names (F213.8, gh-UI/docs: radio jargon ("bed", "liner", "imaging", "ident", "patter") needs a plain name or a one-line explanation wherever it appears #707). Show "Engine settings: in sync", "Restart the engine to apply" or "Unknown". No radio jargon.
• On restartNeeded, list the differing settings by their label, e.g. "Shortest song overlap (crossfade)", not the env key. Say that docker compose restart engine applies them.
• Place it with the existing health tiles or the Sound settings group. Pick whichever reads more naturally.
• Show key names only, never values; the status block doesn't carry values.

📎 Context

• Out of scope for F213 / gh-Engine boots before the api and silently uses fallback tuning on every fresh up #879, where the status field is the contract. This issue tracks the follow-up.
• A saved engine-restart setting already returns applyMode. This tile closes the loop: it confirms the restart actually happened.