feat: add docker healthcheck for Coolify

dockerfile

@@ -45,6 +45,9 @@ ENV NEXT_TELEMETRY_DISABLED 1
 RUN addgroup --system --gid 1001 nodejs
 RUN adduser --system --uid 1001 nextjs
 
+# Install curl for healthcheck
+RUN apt-get update && apt-get install -y curl && rm -rf /var/lib/apt/lists/*
+
 COPY --from=builder /app/public ./public
 COPY --from=builder --chown=nextjs:nodejs /app/.next/standalone ./
 COPY --from=builder --chown=nextjs:nodejs /app/.next/static ./.next/static
@@ -55,4 +58,7 @@ EXPOSE 7777
 ENV PORT 7777
 ENV HOSTNAME "0.0.0.0"
 
+HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
+    CMD curl -f http://localhost:7777/api/health || exit 1
+
 CMD ["node", "server.js"]