Add Windows Security Guide: Top 50 Critical LOLBAS Documentation

Created comprehensive security documentation for the top 50 most critical
Living Off The Land Binaries, Scripts and Libraries (LOLBAS) for Windows 11.

Documentation includes:
- Main README with overview, threat landscape, and usage guide
- Executive Summary with risk assessment and actionable recommendations
- Analysis of 198 Windows 11-compatible LOLBAS entries
- Quick reference tables for all 50 critical binaries
- MITRE ATT&CK technique mappings
- Attack chain analysis and defensive strategies

This provides security teams with comprehensive guidance on understanding,
detecting, and preventing LOLBAS-based attacks on Windows 11 systems.

Author: claude