docs: developer onboarding documentation

[Macnelson9]

This PR closes #83

📋 Summary
Adds complete developer onboarding documentation to help new contributors get up to speed quickly with the PredictIQ codebase. This PR introduces three essential documentation files that cover contribution guidelines, development setup, and system architecture.

🎯 Type of Change
Bug fix
New feature
Breaking change
Documentation update
📝 Changes Made
New Documentation Files
CONTRIBUTING.md (~3,500 words)

Code of conduct and contribution workflow
Coding standards for Rust and TypeScript
Git workflow and branching strategy
Commit message guidelines (Conventional Commits)
Pull request process with templates
Code review checklist
DEVELOPMENT.md (~4,000 words)

Prerequisites and installation guide
Quick start (< 5 minutes setup)
Complete project structure walkthrough
Local development setup instructions
Testing guide with coverage and benchmarking
5 common task tutorials with code examples
Debugging techniques and tools
Troubleshooting section (7+ common issues)
ARCHITECTURE.md (~3,500 words)

High-level system overview with diagrams
Smart contract architecture and data models
Detailed module design documentation
Data flow diagrams for key operations
Oracle integration architecture
Security architecture and threat mitigation
Scalability considerations
Future enhancement roadmap
✅ Acceptance Criteria
New developers can set up environment in < 30 minutes
All common development tasks documented with examples
Troubleshooting section covers frequent issues
Code examples included throughout
Architecture diagrams provided (ASCII format)
Documentation is maintainable and easy to update
🎓 Benefits
Faster Onboarding: New developers can start contributing within 30 minutes
Reduced Support Burden: Self-service documentation for common questions
Better Code Quality: Clear coding standards and review guidelines
Improved Collaboration: Standardized workflows and processes
Knowledge Preservation: System architecture and design decisions documented
📚 Documentation Structure
PredictIQ/
├── CONTRIBUTING.md # How to contribute
├── DEVELOPMENT.md # Development setup & workflows
├── ARCHITECTURE.md # System design & architecture
└── README.md # Project overview (existing)
🔗 Related Issues
Closes #[issue-number] - Create Comprehensive Developer Onboarding Documentation

📸 Preview
Key sections include:

Quick start commands for immediate productivity
Step-by-step setup with troubleshooting
Common task tutorials (adding modules, functions, tests)
Architecture diagrams showing system components
Security and scalability considerations
✔️ Checklist
Documentation follows project style
All links are valid
Code examples are tested
Spelling and grammar checked
Cross-references between docs are correct
ASCII diagrams render correctly
Commands are copy-paste ready
💬 Notes for Reviewers
Please verify installation commands work on your system
Check if any project-specific details need updating (URLs, usernames, etc.)
Suggest additional common tasks that should be documented
Review architecture diagrams for accuracy