feat: add marketplace metrics, privacy features, and service registry endpoints

- Add Prometheus metrics for marketplace API throughput and error rates with new dashboard panels
- Implement confidential transaction models with encryption support and access control
- Add key management system with registration, rotation, and audit logging
- Create services and registry routers for service discovery and management
- Integrate ZK proof generation for privacy-preserving receipts
- Add metrics instru

docs/developer/contributing.md

@@ -0,0 +1,99 @@
+---
+title: Contributing
+description: How to contribute to the AITBC project
+---
+
+# Contributing to AITBC
+
+We welcome contributions from the community! This guide will help you get started.
+
+## Ways to Contribute
+
+### Code Contributions
+- Fix bugs
+- Add features
+- Improve performance
+- Write tests
+
+### Documentation
+- Improve docs
+- Add examples
+- Translate content
+- Fix typos
+
+### Community
+- Answer questions
+- Report issues
+- Share feedback
+- Organize events
+
+## Getting Started
+
+### 1. Fork Repository
+```bash
+git clone https://github.com/your-username/aitbc.git
+cd aitbc
+```
+
+### 2. Setup Development Environment
+```bash
+# Install dependencies
+pip install -r requirements-dev.txt
+
+# Run tests
+pytest
+
+# Start development server
+aitbc dev start
+```
+
+### 3. Create Branch
+```bash
+git checkout -b feature/your-feature-name
+```
+
+## Development Workflow
+
+### Code Style
+- Follow PEP 8 for Python
+- Use ESLint for JavaScript
+- Write clear commit messages
+- Add tests for new features
+
+### Testing
+```bash
+# Run all tests
+pytest
+
+# Run specific test
+pytest tests/test_jobs.py
+
+# Check coverage
+pytest --cov=aitbc
+```
+
+### Submitting Changes
+1. Push to your fork
+2. Create pull request
+3. Wait for review
+4. Address feedback
+5. Merge!
+
+## Reporting Issues
+
+- Use GitHub Issues
+- Provide clear description
+- Include reproduction steps
+- Add relevant logs
+
+## Code of Conduct
+
+Please read and follow our [Code of Conduct](https://github.com/aitbc/blob/main/CODE_OF_CONDUCT.md).
+
+## Getting Help
+
+- Discord: https://discord.gg/aitbc
+- Email: dev@aitbc.io
+- Documentation: https://docs.aitbc.io
+
+Thank you for contributing! 🎉