[@xstate/store] Add event persistence

[davidkpiano]

Add strategy: 'event' option to the persist extension. Instead of persisting context snapshots, this persists the event log and replays events on rehydration to reconstruct state.

Also adds isHydrated(store) helper to check hydration status.

const store = createStore({
  context: { count: 0 },
  on: { inc: (ctx) => ({ count: ctx.count + 1 }) }
}).with(
  persist({
    name: 'my-store',
    strategy: 'event',
    maxEvents: 100
  })
);

[changeset-bot]

🦋 Changeset detected

Latest commit: f646b47

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 7 packages

Name	Type
@xstate/store	Minor
@xstate/store-angular	Patch
@xstate/store-preact	Patch
@xstate/store-react	Patch
@xstate/store-solid	Patch
@xstate/store-svelte	Patch
@xstate/store-vue	Patch

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