Create DEVELOPERS_START_HERE.md documentation

[Thinkersbluff]

Create developer-focused documentation and onboarding guide.

Tasks:

• Development Environment Setup (Docker, VS Code, etc.)
• Repository Structure Guide explaining new organization
• Contribution Workflow and coding standards
• Testing Requirements and validation procedures
• Advanced Configuration and customization

Acceptance Criteria:

• Developers can set up environment following docs alone
• Both novice and experienced developers find appropriate detail
• Contribution process clearly documented
• Testing procedures comprehensive

Dependencies: Move documentation files
Estimate: 4 story points

[Thinkersbluff]

Accidentally created - cleaning up