[Fix] Fix react-colyseus client

[Miniontoby]

The client package of the react-colyseus example was missing the typescript (and ts-node) package in the package.json. These are needed when running pnpm build, since that calls tsc and then vite build.

And because the tsc also builds the server code, the experimentalDecorators also needs to be added in the tsconfig.json of the client. The server's tsconfig.json file already has it, but it is also needed in the client cause else you would get errors like:

../server/src/entities/State.ts:16:4 - error TS1240: Unable to resolve signature of property decorator when called as an expression.
  Argument of type 'undefined' is not assignable to parameter of type 'Object'.

16   @type('string')
      ~~~~~~~~~~~~~~

The client seems to build the server code since the client wants to include some of the server entities files.

So this all fixes it.

Kind Regards,

• Miniontoby

P.s. Really nice you guys finally released this SDK!