chore: add instructions on node version syncing to the README

[SerhiiYahdzhyiev]

Motivation

npm ci fails for more modern versions of node, even though package-lock.json is in place.

Tested with lts/jod from nvm.

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[SerhiiYahdzhyiev]

UPD: I've also updated the launch instructions, since there is no serve script in package.json...