[ServiceWorker] Create F2F agenda (#806)

I'll convert this to a wiki page once we have something more concrete, but an issue seems easier for discussion.

Things I'd like to cover (in priority order)

* Outstanding V1 issues, as we did in Sapporo, but hopefully won't take as long
* Cache API enhancements (since we're likely to have @wanderview around), especially transactions & making `addAll` more useful
* Foreign fetch
* Navigation handling (how to launch as-homescreen from `openWindow` & native apps, and how to manage "single" vs "multi" window sessions)

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Reply to this email directly or view it on GitHub:
https://github.com/slightlyoff/ServiceWorker/issues/806