atom.INTERNAL_onInit hook to support sync effects

[dmaskasky]

Summary

1. Adds a new atom api, atom.INTERNAL_onInit = (store: Store, atomState: AtomState) => void.
   Fires when the atomState is first created in the store for that atom.

2. Updates store.unstable_derive api to add a new callback param, atomOnInit. This is the interceptor for the atom.unstable_onInit api. Since getAtomState is where atom.unstable_onInit is called, we must add atomOnInit to the getAtomState params. atomOnInit accepts a store arg so that the current store is always passed.

Supplemental

• adds initial test for synchronous effect

Check List

• pnpm run prettier for formatting code and docs

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Name	Status	Preview	Comments	Updated (UTC)
jotai	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Dec 23, 2024 3:10am

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Latest commit: 8a22c4b
Last updated: Dec 23, 2024 3:10am (UTC)

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