refactoring 1. step

Dockerfile

@@ -25,7 +25,9 @@ RUN npm install --omit=dev
 # Copy application files
 COPY server.js ./
 COPY qbo_helper.js ./
+COPY src ./src
 COPY public ./public
+COPY templates ./templates
 
 # Create uploads directory
 RUN mkdir -p public/uploads && \
@@ -38,5 +40,5 @@ EXPOSE 3000
 HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
     CMD node -e "require('http').get('http://localhost:3000/api/customers', (r) => {if (r.statusCode !== 200) throw new Error(r.statusCode)})"
 
-# Start server
-CMD ["node", "server.js"]
+# Start server (using modular entry point)
+CMD ["node", "src/index.js"]