add docker health checks

ui/Dockerfile

@@ -1,4 +1,4 @@
-FROM node:24-slim AS base
+FROM node:24-alpine AS base
 
 ENV PNPM_HOME="/pnpm"
 ENV PATH="$PNPM_HOME:$PATH"
@@ -24,8 +24,9 @@ FROM base AS runner
 COPY --from=prod /app/node_modules /app/node_modules
 COPY --from=build /app/build build/
 
-EXPOSE 3000
 
+ENV PORT=3000
 ENV NODE_ENV=production
+EXPOSE $PORT
 
 CMD ["node", "build"]