Add comprehensive project explanation document

[Claude]

Added PROJECT_EXPLANATION.md to provide complete technical overview of the agentic DevOps demonstration project.

Content Overview

• Architecture deep-dive: Data flow, entity relationships, integration patterns (Circuit Breaker, Repository, DTO, Caching)
• Agentic approach: Custom GitHub Copilot agents (Planner, Coder, Designer, Orchestrator, Enterprise Architect) and their workflows
• Technical stack: React 18 + Vite frontend, Spring Boot 3.x + H2 backend, BIAN API v13.0.0 integration
• Testing strategy: JUnit 5 backend tests, Playwright E2E (32+ scenarios, multi-browser/viewport)
• Deployment: Docker multi-stage builds, Azure Container Apps, GitHub Actions CI/CD
• Quick reference: API endpoints, database schema, project structure, getting started

Why

Existing README provides quick-start only. This adds depth for understanding:

• How custom AI agents accelerate development
• BIAN banking standards integration patterns
• Resilience strategies (circuit breaker, fallback, caching)
• Modern React patterns (React Query over Redux)
• Production containerization practices

Complements IMPLEMENTATION_SUMMARY.md (what was built) with architectural rationale and agentic workflow documentation.

Original prompt

explain this project

The user has attached the following file paths as relevant context:

• .github\copilot-instructions.md

Created from VS Code.