Sync automerge CRDT datastructure via e2e encrypted updates

[nikgraf]

This PR sync an automerge document (using a hardcoded ID) via encrypted messages.

Initially I tried to build a automerge-repo-network adapter, but since the protocol is hardcoded and requires two roundtrips I gave up on the idea. Especially it would be very tricky to reverse engineer how to fake the first round-trip on sending/receiving an update. Instead I updated for manual manipulation of the document, but still leveraging the automerge-repo infrastructure so we can added cross-tab communication and the storage adapter from it.

Also switched from useState to @xstate/store for document storage since I needed to access the state (space and it's keys) outside of react. Makes sense anyway since soon we want to move to a solution that's also persisted in IndexedDB.

In addition I upgraded to the latest alphas since this maps the main repositories and has several simplifications e.g. awaitingNetwork state has been removed.

More info can be found here: https://automerge.org/docs/repositories/

There are several follow up tasks that I added here: #62

[cmwhited]

I am a big xstate fan. It looks like most of this impl is in the events app. An open question (not for this PR, specifically) but do you see a pkg that exposes xstate functionality being something useful?

[nikgraf]

@cmwhited not sure, secsync https://github.com/nikgraf/secsync/blob/main/packages/secsync/src/createSyncMachine.ts is built on top of a xstate machine and was exported so you could use the machine directly.

The hooks then used it internally https://github.com/nikgraf/secsync/blob/main/packages/secsync-react-automerge/src/useAutomergeSync.ts

There is some overlap between what Effect can do and xState e.g. automatic retries can be mapped as multiple states or be managed by Effect. Here I'm not sure yet what makes more sense. Depends a bit on our requirements.