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.

.env.example

@@ -0,0 +1,28 @@
+# ==================================
+# ANEXO76 - Variables de Entorno
+# ==================================
+
+# ----- PostgreSQL App -----
+POSTGRES_APP_PASSWORD=postgres
+
+# ----- PostgreSQL Keycloak -----
+POSTGRES_KEYCLOAK_PASSWORD=postgres
+
+# ----- Keycloak Admin -----
+KEYCLOAK_ADMIN=admin
+KEYCLOAK_ADMIN_PASSWORD=admin
+
+# ----- Keycloak Configuración -----
+KEYCLOAK_REALM=master
+KEYCLOAK_CLIENT_ID=anexo76-backend
+KEYCLOAK_CLIENT_SECRET=dev-secret
+KEYCLOAK_FRONTEND_CLIENT_ID=anexo76-frontend
+
+# ----- Backend -----
+DEBUG=True
+ENVIRONMENT=development
+
+# ----- Frontend -----
+NODE_ENV=development
+PUBLIC_API_URL=http://localhost:8000
+PUBLIC_KEYCLOAK_URL=http://localhost:8080