chore: session max age note

[patrick-hofmann]

I've added a note and example since it is not obvious that maxAge of the session is not the same as maxAge of the cookie

[atinux]

Hi @patrick-hofmann

Actually we use maxAge to set the cookie expiration, see https://github.com/unjs/h3/blob/7324eeec854eecc37422074ef9f2aec8a5e4a816/src/utils/session.ts#L141

As the session is stored in the cookie, it expires at the same time the cookie expires.

[patrick-hofmann]

Hi @atinux

you are right, indeed session and cookie lifetime are equal in the current example. Nevertheless this documentation PR also shows why I've created the two PRs

#255 - cookies shall live as short as possible and lifetime should extend while in usage (this could also be achived with a kind of session rotation)

and

#257 - the session lifetime shall end immediately when the user is logged out.

Best regards!