Turbo Streams - Custom Stream Actions - pushState

Premise In Challenge 19 — building on Challenge 8 (inline stream tags) and Challenge 9 (custom actions) — we stored ephemeral state in localStorage. That worked, but the browser’s Back and Forward buttons don’t know about it. Hit Back after switching versions three times? You leave the page entirely. history.pushState() fixes this — but the part most people overlook is the first argument: the…