Improve Cancel Incident UI Action - Enhanced Documentation and Error Handling

[Shashank0701-byte]

📋 Summary

Enhanced the existing Cancel Incident UI Action with improved documentation, error handling, and user experience.

🔧 Changes Made

• Enhanced Documentation: Comprehensive README.md with features, configuration, and usage details
• Setup Guide: Added SETUP.md with step-by-step implementation instructions
• Improved Code Quality: Added error handling, validation, and audit logging
• Better UX: Enhanced confirmation dialog and user feedback messages
• Code Documentation: Added JSDoc-style comments for better maintainability

📁 Files Modified/Added

• README.md - Enhanced with comprehensive documentation
• script.js - Improved with error handling and validation
• SETUP.md - New file with detailed setup instructions

✅ Testing

• Validated JavaScript syntax and logic
• Verified documentation completeness
• Ensured proper ServiceNow API usage

Fixes #2299

[ravichandra1998g]

looks good to me.