docs: Add comprehensive development guide for new developers

[devin-ai-integration]

Add Comprehensive Development Guide

This PR adds a comprehensive development guide for new developers in the docs/DEVELOPMENT.md file. The guide includes:

• Project overview and structure
• Setup instructions for both Docker and local development
• Development workflow guidance
• Testing and code quality information
• Troubleshooting tips
• Contributing guidelines

Testing

• Verified markdown formatting
• Ensured all sections are clear and comprehensive

Link to Devin run: https://app.devin.ai/sessions/a307cfceb14a4078b84aeea0eb016680
Requested by: Hal Seki ([email protected])

[devin-ai-integration]

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