[Start] Missing docs for `setCookie()` and `getCookie()`

[Zev18]

There seems to be no docs for the setCookie(), getCookie(), and other methods from @tanstack/react-start/server.

Although there's docs on creating sessions using useSession(), there's nothing on setting and getting cookies manually.

Some examples in the Authentication section for implementing JWTs would be particularly helpful.

[valerii15298]

This should go to https://github.com/TanStack/router since this repo is just for rendering docs

It is mentioned in the hydration example: https://github.com/TanStack/router/blob/main/docs/start/framework/react/guide/hydration-errors.md?plain=1#L22

But no any docs for it...