Update installation scripts and documentation

- Enhanced install.sh with better error handling and multi-shell support
- Updated configuration files (CLAUDE.md, MCP.md, RULES.md) to latest version
- Added comprehensive CONTRIBUTING.md guidelines
- Improved README.md formatting and clarity
- Fixed Commands_Cheat_Sheet.md formatting
- Updated .gitignore with better exclusions
- Minor LICENSE and CHANGELOG.md updates

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

CONTRIBUTING.md

@@ -195,6 +195,18 @@ Description & purpose
 - Use discussions for questions
 - Tag maintainers for urgent issues
 
+## Developer Certificate of Origin (DCO)
+
+By contributing to this project, you agree to the Developer Certificate of Origin (DCO). This document was created by the Linux Kernel community and is a simple statement that you, as a contributor, have the legal right to make the contribution.
+
+The DCO is legally binding statement that assures contributors have the right to submit their work under the project's license. All commits must be signed off with:
+
+```
+git commit -s -m "Your commit message"
+```
+
+This adds a `Signed-off-by` line to your commit message.
+
 ## Recognition
 
 Contributors are recognized through:
@@ -203,6 +215,9 @@ Contributors are recognized through:
 - Issue/PR acknowledgments
 - Community discussions
 
+### Notable Contributors
+- @amgiiine - Commands Cheat Sheet and documentation improvements
+
 ---
 
 **Ready to contribute?** Create an issue or submit a PR!