Author service worker cache strategies (cache-first, network-first, stale-while-revalidate, cache-only, network-only) per Workbox conventions, plus generate the matching Playwright assertions to lock the strategy in. Avoids the common "cached forever" pitfall by enforcing TTL + version-bump invalidation. Use when a new route needs defined offline behavior, when a hand-rolled `sw.js` is being moved to Workbox strategies, or when users report seeing stale content after a deploy.