H4 — does stale-while-revalidate remove the guest's wait?

Real browser, real network, real paint. Timings are click → cards laid out (forced synchronous layout, immune to background-tab throttling), not time-to-JSON. Same upstream call and one shared cache entry for both modes; only the policy differs. Fresh window 20s so an entry can go stale inside one run.

#stepmodeserved age sserver msupstream ms RENDERED mshotelscheapest