[BUG] Project-local skills interfere with global slash command fuzzy matching

Bug Report

Issue: Skills fuzzy matching cache not cleared after removing project-local skills

Version: 2.1.29

Description:
After defining project-local skills in .claude/skills/ and then removing them:

1. Claude Code prompts to install the removed skills
2. The fuzzy matching still finds the old skill names (case-insensitive matching appears broken)

Root Cause: Found a skill file that was not UTF-8 encoded. After deleting this specific skill file, the issue was resolved.

Steps to Reproduce:

1. Create a .claude/skills/ directory with custom skills
2. Use the skills in a session
3. Remove the skills directory
4. Claude still prompts for the removed skills

Expected Behavior: Skills should be fully cleared from memory when removed

Workaround: Delete any non-UTF-8 encoded skill files