feat(gtm-audit): Add GTM audit skill with Notion integration
- Automated GTM container detection and validation
- DataLayer event validation against GA4 specs
- Form tracking analysis and interaction simulation
- E-commerce checkout flow analysis
- Multi-platform support (GA4, Meta, LinkedIn, Google Ads, Kakao, Naver)
- Notion database export with detailed reporting
- Korean market considerations
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>