Add Node.js Hello World application with Docker support

- Added index.js: Simple HTTP server on port 3000
- Added package.json: NPM configuration
- Added Dockerfile: Multi-stage Docker build
- Added .dockerignore: Exclude unnecessary files from build

Ready for Coolify deployment via CI/CD pipeline.

Dockerfile

@@ -0,0 +1,13 @@
+FROM node:18-alpine
+
+WORKDIR /app
+
+COPY package.json .
+
+RUN npm install --production
+
+COPY . .
+
+EXPOSE 3000
+
+CMD ["npm", "start"]