Initial commit: HK Planner app

Housekeeping workload and hours planning app — port of the WP hotel
housekeeping hours calculator plugin. 7-day occupancy planner with
Newbook PMS integration, staff rota, time requirements, and pickup tracking.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/Dockerfile

@@ -0,0 +1,7 @@
+FROM node:22-alpine
+WORKDIR /app
+COPY package.json .
+RUN npm install --omit=dev
+COPY src ./src
+EXPOSE 3001
+CMD ["node", "src/index.js"]