feat: add health check endpoint and update Docker Compose healthcheck configuration

docker-compose.yml

@@ -26,8 +26,14 @@ services:
     environment:
       DATABASE_URL: postgresql://${POSTGRES_USER}:${POSTGRES_PASSWORD}@db:5432/${POSTGRES_DB}
     ports:
-      - "${PORT:-8080}:8080"
+      - "${PORT:-8080}:${PORT:-8080}"
     depends_on:
       db:
         condition: service_healthy
+    healthcheck:
+      test: ["CMD-SHELL", "curl -f http://localhost:${PORT:-8080}/health || exit 1"]
+      interval: 10s
+      timeout: 5s
+      retries: 5
+      start_period: 10s