Add comprehensive Mermaid diagrams for Craftista microservices architecture

[Copilot]

This PR adds detailed Mermaid diagrams documenting the complete microservices architecture of the Craftista application, showing how each service connects and communicates with others.

What's Added

📋 Complete Architecture Documentation (docs/craftista-microservices-architecture.md)

• Comprehensive Mermaid diagram showing all 4 microservices and their relationships
• Technology stack details for each service (Node.js, Python, Go, Java)
• Database connections and data storage patterns
• Complete API endpoint mapping for all services
• Configuration and service discovery patterns

🔄 Communication Flow Diagram (docs/microservices-communication-flow.md)

• Request routing visualization showing how requests flow between services
• Synchronous API calls between Frontend and backend services
• Asynchronous data synchronization pattern (Voting ↔ Catalogue every 60s)
• Step-by-step communication examples for common user flows

Architecture Overview

The diagrams reveal the following microservices architecture:

User → Frontend (API Gateway) → Backend Services → Databases
     ←           ←                    ←              ←

• Frontend Service (Node.js/Express:3000): Acts as API Gateway routing all user requests
• Catalogue Service (Python/Flask:5000): Manages origami catalog and product data
• Recommendation Service (Go/Gin:8080): Provides daily origami recommendations
• Voting Service (Java/Spring Boot:8080): Handles voting functionality with periodic data sync

Key Communication Patterns Documented

1. API Gateway Pattern: Frontend service routes all user requests to appropriate backends
2. Service-to-Service Sync: Voting service periodically fetches origami data from Catalogue
3. Database Per Service: Each microservice maintains its own isolated database
4. Health Monitoring: All services expose status endpoints aggregated by Frontend

Benefits

• Visual Architecture Reference: Clear understanding of service dependencies and data flow
• Developer Onboarding: New developers can quickly understand the system architecture
• DevOps Planning: Useful for containerization, orchestration, and deployment strategies
• Documentation Completeness: Supplements existing architecture diagrams with technical details

The main README.md has been updated to reference these new architectural resources, making them easily discoverable for developers and DevOps practitioners working with the Craftista application.

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