feat: Add frontend and backend initialization scripts, implement Keycloak and PostgreSQL setup

- Implemented SvelteKit frontend with authentication callback handling.
- Created demo routes and paraglide localization functionality.
- Added health check and entrypoint scripts for backend services.
- Established PostgreSQL and Keycloak initialization scripts with health checks.
- Introduced models for database schema using SQLAlchemy.
- Configured Vite and SvelteKit for development and testing environments.
- Added health check script to verify service statuses and resource usage.
- Created Docker entrypoint scripts for seamless service startup.

backend/.env.example

@@ -0,0 +1,29 @@
+# Application
+APP_NAME=Anexo76
+APP_VERSION=1.0.0
+DEBUG=True
+ENVIRONMENT=development
+
+# Database - Core (Shared)
+CORE_DB_HOST=localhost
+CORE_DB_PORT=5432
+CORE_DB_NAME=anexo76_core
+CORE_DB_USER=postgres
+CORE_DB_PASSWORD=postgres
+
+# Keycloak
+KEYCLOAK_SERVER_URL=http://localhost:8080
+KEYCLOAK_REALM=master
+KEYCLOAK_CLIENT_ID=anexo76-backend
+KEYCLOAK_CLIENT_SECRET=your-client-secret
+
+# Security
+SECRET_KEY=your-secret-key-change-in-production
+ALGORITHM=HS256
+ACCESS_TOKEN_EXPIRE_MINUTES=30
+
+# CORS
+CORS_ORIGINS=http://localhost:5173,http://localhost:3000
+
+# License Service
+LICENSE_CHECK_ENABLED=True