[Website] Invalidate all the cache layers, correctly ship the new WordPress releases

[adamziel]

After the recent WordPress update from 6.6.1 to 6.6.2, Playground kept installing 6.6.1 in my web browser until I did an explicit cache refresh. Let's make sure these updates work without any user intervention (after the redesign work is finished).

Let's also map out all the cache layers Playground has and discuss an automated workflow to make sure they're all invalidated as needed. Let's also see if we can consolidate some of the layers. Here's a few I can think of:

• HTTP cache in the browser
• CacheStorage in a few scripts
• ServiceWorker cache
• OPFS files (website files only)
• localStorage (I can't remember what, but it caches something)
• IDB (directory handles only)
• Edge cache on playground.wordpress.net
• ...anything else?

cc @brandonpayton @bgrgicak

[bgrgicak]

I think this is the full list.

Let's also map out all the cache layers Playground has and discuss an automated workflow to make sure they're all invalidated as needed.

Let's do this when we meet next time.