Bug: /compact + /rename session not resumable by slug/name, only by UUID

Bug Report

Summary

After running /compact, the new session inherits the same slug as the previous session. When /rename is used to assign a custom title, the session cannot be resumed by slug or custom name — only by UUID. The session picker also hides the post-compact session when a duplicate slug exists.

Steps to Reproduce

1. Start a session and run /compact → a new session is created (new UUID, same slug inherited from the previous session)
2. Run /rename <unique-name> to assign a custom title to the new session
3. End the session and open a new claude instance
4. Try to resume via the interactive picker (/resume) or claude --resume <name>

Expected Behavior

• The renamed session should appear in the resume picker
• claude --resume <slug> and claude --resume <custom-name> should both work
• /compact-derived sessions should be distinguishable and resumable independently

Actual Behavior

• The session does not appear in the interactive resume picker
• claude --resume <slug> fails (slug is shared with the pre-compact session, picker only shows one entry per slug)
• claude --resume <custom-name> (the name set via /rename) also fails
• Only claude --resume <UUID> works

Root Cause Analysis

• /compact creates a new session that inherits the same slug as the previous session
• The resume picker appears to show only one entry per slug → the post-compact session is hidden behind the pre-compact one
• /rename sets a customTitle, but this title is not indexed or matched in the resume picker or --resume flag lookup
• Even --resume <slug> fails to reliably target the correct (latest) session when multiple sessions share the same slug

Environment

• Claude Code version: v2.1.71
• OS: WSL2 (Ubuntu on Windows)
• Shell: bash

Additional Notes

A reasonable fix would involve one or more of:

1. Assigning a new, unique slug to sessions created by /compact instead of inheriting the parent slug
2. Making the resume picker show all sessions with the same slug (e.g. with timestamp disambiguation), not just one
3. Making --resume and the picker search by customTitle (set via /rename) in addition to slug and UUID

This makes post-compact sessions effectively unresumable by human-readable name, which undermines the utility of both /compact and /rename.