fix(api): graceful shutdown, единый обработчик ошибок и корректные 404

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

deploy/docker/authportal/Dockerfile

@@ -52,6 +52,7 @@ ENV NODE_ENV=production \
 COPY --from=build --chown=node:node /out ./
 USER node
 EXPOSE 8080
+STOPSIGNAL SIGTERM
 VOLUME ["/data"]
 HEALTHCHECK --interval=30s --timeout=5s --start-period=10s --retries=3 \
   CMD ["node", "-e", "fetch('http://127.0.0.1:8080/health').then(r=>process.exit(r.ok?0:1)).catch(()=>process.exit(1))"]