Rewrite README and add comprehensive API documentation for open-source Google Cloud Run alternative

[Copilot]

This PR transforms the Container Engine project documentation to clearly position it as an open-source alternative to Google Cloud Run with comprehensive user management capabilities, built on a modern Rust + Axum backend architecture.

Key Changes

README.md Updates

• Repositioned as Google Cloud Run Alternative: Added clear messaging that this is an open-source alternative to Google Cloud Run with the subtitle "An Open-Source Alternative to Google Cloud Run - Built with Rust & Axum"

• Enhanced Feature Organization: Restructured the Key Features section into three categories:

  • User Management System: Registration, authentication, API key management, and user dashboard
  • Container Deployment & Management: Core deployment features
  • Technical Features: Backend technology stack and infrastructure capabilities

• Added Technology Stack Section: Detailed the modern tech stack including:

  • Rust with Axum framework for high-performance, memory-safe backend
  • PostgreSQL, Kubernetes, JWT authentication, Prometheus monitoring
  • Structured logging with correlation IDs

• Updated Development Instructions: Changed from npm-based setup to Rust/Cargo workflow with proper installation and build commands

New APIs.md Documentation

Created comprehensive API documentation (899 lines) covering all essential endpoints for a complete container platform:

• Authentication & User Management: Registration, login, token refresh, logout
• API Key Management: Create, list, and revoke API keys for programmatic access
• User Profile Management: Profile updates and password changes
• Container Deployment: Full CRUD operations for container deployments with environment variables, health checks, and resource limits
• Scaling & Management: Start, stop, scale, and update deployments
• Custom Domain Support: Add and manage custom domains with automatic SSL
• Monitoring & Logging: Real-time logs, performance metrics, and deployment status
• WebSocket Events: Real-time deployment status updates
• Error Handling: Consistent error responses and rate limiting

The API documentation includes detailed request/response examples, error codes, rate limiting information, and WebSocket event specifications, providing everything needed to implement a production-ready container deployment platform.

This documentation now accurately reflects the project's scope as a comprehensive, open-source container engine with full user management capabilities, similar to Google Cloud Run but with the transparency and flexibility of open-source software.

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