Fix frontend health check: Install curl in Alpine container

- Added apk add curl to frontend Dockerfile
- Fixes unhealthy container status by enabling health check to work
- Health check now properly tests http://localhost:806

frontend/Dockerfile

@@ -24,6 +24,9 @@ EXPOSE 806
 # Set port environment variable
 ENV PORT=806
 
+# Install curl for health check
+RUN apk add --no-cache curl
+
 # Health check
 HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
   CMD curl -f http://localhost:806 || exit 1