Feature Request: /sessionsave command as intuitive alternative to /rename for session persistence

Problem

The current /rename command is the only way to give a session a name before exiting. However, the word "rename" implies changing an existing name — not saving/persisting a session for later retrieval.

When working on a project and wanting to pause (via /exit) and resume later, the mental model is saving the session, not renaming it.

Proposal

Add a dedicated command like /sessionsave <name> (or /session save <name>) that clearly communicates the intent: "I want to save this session so I can resume it later."

Example workflow:

# Working on a feature...
/sessionsave meine-feature-step-3
/exit

# Later:
claude --resume meine-feature-step-3

Why this matters

• /rename is semantically misleading — users don't think of it as the "save session" action
• A /sessionsave command would be more discoverable and intuitive
• It better matches the mental model of "pause and resume" workflows