Add /rename command to rename the current session from within an active conversation

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

Problem

Currently, sessions can only be renamed via the /resume dialog using Ctrl+R. There is no way to name or rename a session while you're actively in it — you have to exit first, then go back and rename retroactively.

Proposed Solution

Add a /rename <name> slash command that sets the current session's display name from within the active conversation.

Example:
/rename Fix JWT auth bug

Why this matters

• Sessions are listed by their first message, which is often not descriptive enough
• Users frequently start a session before knowing what it will grow into
• Naming sessions mid-conversation enables better organization without interrupting flow
• This is especially useful for long-running sessions that evolve over time

Alternatives Considered

• Renaming via /resume (Ctrl+R) — works but requires leaving the current session
• No plugin/MCP hook exists today to implement this as a community extension

Proposed Solution

Add a /rename <name> slash command that sets the current session's display name from within the active conversation.
Example:
/rename Fix JWT auth bug

This would update the session name immediately, so it appears correctly in the /resume session list going forward.

Alternative Solutions

_No response_

Priority

Low - Nice to have

Feature Category

CLI commands and flags

Use Case Example

I start a session with a vague question like "how do I structure this?" — the session gets named after that first message. Twenty minutes later it has grown into a full refactor discussion. At that point I want to rename it to something meaningful like "Refactor auth middleware", but I have to exit the session, go into /resume, find it, and rename it there — breaking my flow entirely.

With /rename, I could just type it inline and move on.

Additional Context

_No response_