[Feature Request] Add custom naming for conversation sessions

Bug Description
Feature Request: Session Renaming

I'd like the ability to rename conversation sessions for better organization.

Current situation: Sessions are identified only by auto-generated IDs, making it difficult to find specific conversations when using /resume.

Proposed feature: Allow users to assign custom names to sessions, either:

• During the session with a command like /name "descriptive title"
• Retroactively when viewing session history
• Via /resume interface with rename option

Use case: When working on multiple projects or features, meaningful session names (e.g., "auth-refactor", "bug-fix-login", "api-design") would make it much faster to locate and resume the right
conversation.

This would significantly improve workflow when context-switching between tasks.

Environment Info

• Platform: darwin
• Terminal: iTerm.app
• Version: 2.0.55