feat: release v2.0.0 - major documentation update and open source release

- Complete rewrite of README with 590+ lines of documentation
- Add comprehensive usage examples for all automation documents
- Add architecture diagrams and best practices
- Create detailed CHANGELOG
- Make repository public for open source community
- Enable security features and vulnerability alerts
- Update package version to 2.0.0
- Add 15 relevant repository topics for discoverability

Author: thomasvincent

CHANGELOG.md

@@ -0,0 +1,73 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [2.0.0] - 2025-10-04
+
+### Added
+- Comprehensive README documentation with 590+ lines
+- Detailed usage examples for all automation documents
+- Architecture diagrams with Mermaid
+- Installation methods (AWS CLI, CloudFormation, Terraform)
+- Best practices section
+- Monitoring and logging guidance
+- Roadmap for future enhancements
+
+### Changed
+- Made repository public for open source community
+- Enhanced documentation for all SSM documents
+- Improved parameter descriptions
+- Updated repository description and topics
+- Restructured README for better navigation
+
+### Security
+- Enabled vulnerability alerts
+- Enabled automated security fixes
+- Added security scanning workflows
+- Documented IAM permission requirements
+
+## [1.0.2] - Previous Release
+
+### Added
+- CloudFront distribution management automation
+- Cost optimization recommendations script
+- Cross-account resource management
+- Lambda function lifecycle management
+- Security group audit and remediation
+- Maintenance window setup automation
+
+### Changed
+- Updated dependencies
+- Improved error handling
+- Enhanced logging
+
+### Fixed
+- Various bug fixes in automation scripts
+
+## [1.0.1] - Previous Release
+
+### Added
+- EC2 instance patching automation
+- S3 bucket encryption automation
+- IAM policy attachment automation
+- Shared Python helper modules
+
+### Changed
+- Improved documentation
+- Enhanced parameter validation
+
+## [1.0.0] - Initial Release
+
+### Added
+- Initial SSM automation documents
+- Basic documentation
+- GitHub Actions workflows
+- MIT License
+
+[2.0.0]: https://github.com/thomasvincent/aws-ssm-automation-scripts/compare/v1.0.2...v2.0.0
+[1.0.2]: https://github.com/thomasvincent/aws-ssm-automation-scripts/compare/v1.0.1...v1.0.2
+[1.0.1]: https://github.com/thomasvincent/aws-ssm-automation-scripts/compare/v1.0.0...v1.0.1
+[1.0.0]: https://github.com/thomasvincent/aws-ssm-automation-scripts/releases/tag/v1.0.0