Skill tool does not search ~/.claude/skills/ or <project>/.claude/skills/

Bug Description

The Skill tool only resolves skills registered in a plugin registry. It does not search:

1. ~/.claude/skills/ — the documented default location for personal skills
2. <project>/.claude/skills/ — the documented default location for project-level skills

When a user runs /resolve-bugbot (stored in ~/.claude/skills/resolve-bugbot.md) or /new-router (stored in <project>/.claude/skills/new-router.md), the Skill tool returns Unknown skill: <name> instead of finding and loading the file.

Expected Behavior

The Skill tool should search in order:

1. ~/.claude/skills/
2. <project>/.claude/skills/
3. Plugin registries (e.g. superpowers)

Actual Behavior

Only plugin-registered skills resolve. Personal and project-level skills always return Unknown skill: <name>.

Workaround

Claude can read the skill file directly via Read and follow it manually — but this requires the user to point Claude to the file, defeating the purpose of the slash command UX.

Environment

• Platform: macOS (darwin 25.2.0)
• Shell: zsh