refactor: reorganize documentation and rules structure

[dgokcin]

Summary

Comprehensive reorganization of the documentation and rules structure, moving from xnotes to a more structured .cursor/rules system. This change implements a cleaner, more maintainable organization for rules, templates, and documentation standards.

Changes

• Migrated content from xnotes/ to structured directories under .cursor/rules/
• Added new organized rule categories:
  • Core rules for rule generation and management
  • Documentation standards and templates
  • Global rules for lessons learned and best practices
  • Tool-specific rules (git, GitHub PR, Kubernetes)
  • Workflow rules for agile and project management
• Removed deprecated xnotes/ directory and related files
• Updated apply-rules.sh script to support new directory structure
• Implemented new template system for standardized documentation

Additional Notes

• All existing functionality has been preserved but reorganized into a more maintainable structure
• New organization provides clearer separation of concerns between different types of rules
• Template system will help ensure consistency in future documentation
• Directory structure now follows a more intuitive pattern for easier navigation
• Previous AI character-based rules have been removed in favor of more professional, standardized guidelines