docs: Add comprehensive CONTRIBUTING.md guide

- Create detailed contribution guidelines following best practices
- Include code of conduct, development setup, and workflow
- Add coding standards, testing guidelines, and PR process
- Include issue reporting templates and documentation standards
- Provide clear instructions for different types of contributions
- Add community guidelines and recognition information

This guide helps new contributors understand how to get started and
contribute effectively to the Flytrap project.

Author: andrewmarconi