[compiler][playground] Upgrade to Next 15.2.0-canary.64

Upgrade compiler playground to use the newest nextjs release, which includes react compiler transform pipeline optimizations https://github.com/vercel/next.js/pull/75676/.

Also made a drive-by fix to avoid the error `Cannot update a component ('Router') while rendering a different component ('StoreProvider'). To locate the bad setState() call inside 'StoreProvider', follow the stack trace as described in https://react.dev/link/setstate-in-render`. The bad setState came from `history.replaceState({}, '', `#${hash}`);`.

Prior to this, playground ran side effects in a reducer (i.e. during render). These have now been moved an effect.