Plugin skill shadows built-in /review command via unqualified name resolution

Bug Description

Typing /review at the Claude Code prompt resolves to a plugin skill (ikh:review) instead of the built-in /review (PR review) command. According to the plugin docs, plugin skills should only be reachable via their namespaced name (e.g., /ikh:review), not the short form.

Steps to Reproduce

1. Install a plugin (e.g., ikh) that has a skill with folder name review (registered as ikh:review)
2. The built-in /review command (PR review) is also available
3. Type /review in the prompt
4. Observe: it expands to the plugin's ikh:review skill instead of the built-in /review

Expected Behavior

/review should resolve to the built-in review command. The plugin skill should only be reachable as /ikh:review (fully qualified with namespace).

The docs explicitly state:

Plugin skills are always namespaced (like /my-first-plugin:hello) to prevent conflicts when multiple plugins have skills with the same name.

Actual Behavior

/review resolves to ikh:review (the plugin skill), making the built-in /review unreachable.

Environment

• Claude Code version: 2.1.101+
• Plugin: custom plugin with name: "ikh" in plugin.json
• Skill: skills/review/SKILL.md with standard frontmatter

Related Issues

• #35585 — Same class of bug: built-in /btw command conflicted with superpowers plugin skill resolution

Suggested Fix

Built-in commands should take priority over unqualified plugin skill name matches. When a user types /review, resolution order should be:

1. Built-in commands (exact match)
2. Plugin skills (exact match on fully-qualified name only)