Some questions: Quit session without logout? Activation?

Entering claude starts a REPL with no clear exit command, and if there is, it is not intuitive for me at least. Currently, the only way to 'exit' seems to be logging out, so I need to login again for each new chat session. I'd like to request adding explicit commands (like /exit or /quit).

Continuing above, since I need to relogin, each session will create a new claude_code_key_* entry in my Anthropic console API keys, and thus cluttering it. Maybe make it be possible to BYOK from environment variable maybe?

Another thing is, the invitation email states: "This invite will expire after 7 days so be sure to activate it soon." But this activation word is unclear to me - is it considered complete after just the first OAuth login? Could you please clarify here?