Revert to bundling service workers for production?

[teemingc]

#16169 made ESM for service workers the default but it's only been baseline since January 2026. But to be fair, it's been supported for 5 years by every browser except Firefox according to MDN. Maybe we want to at least include an option to continue bundling it?

[teemingc]

Decision: service workers not working for older Firefox versions is not a major blocker so we can punt on this