[BUG] Skills UI: Conflict and hiding of local skills when plugin package name == local skill name (edge case bug)

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

I found an edge-case bug in the /skills interface: when a plugin's package name is exactly the same as a local skill name, the two skills conflict and one is hidden in the UI, even though their full qualified names are different.

What Should Happen?

Other duplicate skills (e.g. frontend-design, webapp-testing) work correctly:
Plugin version: has unique namespace prefix (e.g. document-skills:frontend-design, example-skills:webapp-testing)
Local version: no prefix
No conflict → both display normally

Error Messages/Logs

Steps to Reproduce

Install a local skill named claude-api at path: ~/.claude/skills/claude-api/
Install an official plugin skill with package name claude-api (full name: claude-api@anthropic-agent-skills)
Open the /skills interface
Only one claude-api skill is displayed; the other is hidden

Claude Model

Not sure / Multiple models

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.79

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_