fix: add HEALTHCHECK to Dockerfile - prevents silent dead container after 24h

Dockerfile

@@ -37,7 +37,12 @@ COPY --from=frontend-builder /app/public ./public
 # HuggingFace Spaces uses port 7860
 EXPOSE 7860
 
+# Health check - confirms both frontend and backend are alive
+# start-period gives time for model warmup before HF marks it unhealthy
+HEALTHCHECK --interval=30s --timeout=15s --start-period=120s --retries=5 \
+  CMD curl --fail --silent http://localhost:7860/ || exit 1
+
 # Copy and run entrypoint
 COPY docker-entrypoint.sh /docker-entrypoint.sh
 RUN chmod +x /docker-entrypoint.sh
-CMD ["/docker-entrypoint.sh"]
+CMD ["/docker-entrypoint.sh"]