dillon1000/react

[compiler][playground] Upgrade to Next 15.2.0-canary.64 (#32428)

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.