Initial commit: Superpowers plugin v1.0.0

Core skills library as Claude Code plugin:
- Testing skills: TDD, async testing, anti-patterns
- Debugging skills: Systematic debugging, root cause tracing
- Collaboration skills: Brainstorming, planning, code review
- Meta skills: Creating and testing skills

Features:
- SessionStart hook for context injection
- Skills-search tool for discovery
- Commands: /brainstorm, /write-plan, /execute-plan
- Data directory at ~/.superpowers/

skills/meta/INDEX.md

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+# Meta Skills
+
+Skills about skills - how to create and use the skills system.
+
+## Available Skills
+
+- skills/meta/installing-skills - Fork, clone, and symlink clank repo to ~/.claude/skills. Use for initial setup, installing clank for the first time.
+
+- skills/meta/creating-skills - How to create effective skills for future Claude instances. Use when you discover a technique, pattern, or tool worth documenting for reuse.
+
+- skills/meta/testing-skills-with-subagents - Iteratively test and bulletproof skills using pressure scenarios and rationalization analysis. Use after writing skills that enforce discipline or rules, before deploying skills agents might want to bypass.
+
+- skills/meta/gardening-skills-wiki - Maintain skills wiki health with automated checks for broken links, naming consistency, and INDEX coverage. Use when adding/removing skills, reorganizing categories, or for periodic maintenance.
+