[FEATURE] Allow naming/renaming conversations

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

When working on multiple tasks across different conversations, it's hard to identify and resume the right one. Currently, conversations are listed by timestamp and an auto-generated summary, which isn't always descriptive enough to quickly find what I need.

Proposed Solution

The ability to assign a custom name/label to a conversation, either at creation time or retroactively. For example:

A /name "Auth refactor" slash command to label the current conversation.
When using claude --resume, display the custom name alongside the timestamp.
Optionally, allow resuming by name: claude --resume "Auth refactor"

Alternative Solutions

Relying on the auto-generated summary, but it's often too generic or doesn't capture the intent of the session.
Starting fresh conversations and re-explaining context, which is inefficient.

Priority

Medium - Would be very helpful

Feature Category

CLI commands and flags

Use Case Example

This would be especially useful for developers who juggle multiple features, bugs, or projects within the same repo and need to context-switch between conversations frequently

Additional Context

_No response_