Embedded key fixes

[oliviathet]

TL;DR: 1 fix + 2 changes for the embedded key that is generated and stored in localStorage:

• [fix] fix keygen to have the right keyops
• [change] expiration for local storage
• [change] RESET event feature

We want to avoid the nightmare situation where we have buggy keys in the user's localStorage. Rather than directing the user from manually debugging/clearing their localStorage, we can add 2 additional controls: 1) The parent page can post a RESET_EMBEDDED_KEY event that we listen to clear the key from localStorage. 2) The key is set in localStorage with an expiration of 48 hours. If it's expired when we're fetching it, we remove it from localStorage and return null. If it should have an expiration but is not saved with an expiration, we also remove it and return null.

TODO: Maybe in a separate PR, we need to figure out a fix for

index.html:890 Uncaught (in promise) Error: decryption failed: M
at HpkeDecrypt (index.html:890:15)
at async onInjectBundle (index.html:809:39)

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[r-n-o]

One piece that's missing: initEmbeddedKey should check for expir

[r-n-o]

If we want an actual event to drive the reset let's have the button click trigger an event on the page like we do for other events:
https://github.com/tkhq/recovery/blob/ce33591723435a64be97830a2a492ef6f7e519a7/index.html#L776-L782

And then you can add another if statement in here to handle the reset case:
https://github.com/tkhq/recovery/blob/ce33591723435a64be97830a2a492ef6f7e519a7/index.html#L753-L762

That way the parent will be able to post a RESET message to an iframe, or we can trigger this even in the standalone page, and the exact same onReset handler will be called.

[oliviathet]

btw initEmbeddedKey checks for expiry by calling getEmbeddedKey (calls getItemWithExpiry) and setEmbeddedKey (setItemWithExpiry)

[r-n-o]

• I think you're missing the event handler for this new event! We should now have a onReset or onClear function to do this (you can rename resetEmbeddedKey
• The even name should be RESET_EMBEDDED_KEY (you have an extra SET in there!)

[oliviathet]

AH im just slipping today >_< thanks for catching this

[r-n-o]

Nice! Looks ready to merge! One final tiny nitpicky thing

[r-n-o]

Nit: I don't think this needs to be exported anymore!

[oliviathet]

i originally kept it for the test, but i think we don't really need to test this unless we want to test all events. and we are already testing the underlying functionality for localStorage getter/setter. so i just removed this and its usage in the test!