feat: Claude Code Plugin Marketplace Reorganization

[tommy-ca]

Summary

Complete reorganization of cc-sdd as a Claude plugins marketplace for modular, standards-compliant installation.

Changes Made

• Marketplace Structure: Created .claude-plugin/marketplace.json defining cc-sdd as a marketplace
• Plugin Development: Built complete cc-sdd-claude-code plugin with 12 commands, 9 agents, and 23 settings files
• Standards Compliance: Full Claude plugins specification compliance with proper plugin.json metadata
• Documentation Updates: Enhanced README with marketplace installation instructions
• Cleanup: Focused exclusively on Claude Code plugin, removed redundant variants

Key Features

• Modular Installation: Install only needed plugins for specific AI agents
• Standards Compliant: Follows official Claude plugin architecture
• Easy Updates: Marketplace-based distribution for seamless updates
• Plugin Isolation: Each agent type is a separate plugin with own settings

Installation

# Add marketplace
claude /plugin marketplace add https://github.com/gotalab/cc-sdd

# Install Claude Code plugin
claude /plugin install cc-sdd-claude-code

Testing

• ✅ All 147 tests passing
• ✅ Plugin structure validated
• ✅ CLI functionality confirmed
• ✅ Marketplace JSON verified

Backward Compatibility

Traditional npx cc-sdd installation remains fully supported.

[tommy-ca]

Closing per request to keep fork-only PR.