user-invocable: false in SKILL.md frontmatter does not hide skills from / menu

Description

Skills with user-invocable: false in their YAML frontmatter still appear in the / slash-command autocomplete menu when a plugin is installed in other projects.

Expected behavior

Skills with user-invocable: false should be hidden from the / menu. They should only be auto-invocable by Claude based on their description, or explicitly invoked by commands.

Actual behavior

Skills appear in the / menu alongside commands, making the menu cluttered with implementation-detail skills that users shouldn't invoke directly.

Reproduction steps

1. Create a plugin with a skill that has user-invocable: false in its SKILL.md frontmatter:

---
name: my-skill
description: "An internal helper skill..."
user-invocable: false
---

1. Install the plugin in a project
2. Type / in Claude Code — the skill appears in the autocomplete list alongside user-facing commands

Example

Plugin: ai-setup-automation

All 10 skills in this plugin have user-invocable: false set correctly, yet they all appear in the / menu in projects where the plugin is installed.

Environment

• Claude Code CLI (latest)
• Plugin structure: plugins/<name>/skills/<skill-name>/SKILL.md