Added optionnal online storage and cross-client sync

docker/Sync.Dockerfile

@@ -0,0 +1,13 @@
+FROM node:24-slim
+WORKDIR /app
+COPY package.json package-lock.json ./
+RUN npm ci --omit=dev
+COPY server ./server
+COPY src/lib/sync/crypto.js src/lib/sync/model.js ./src/lib/sync/
+COPY src/lib/backup.js src/lib/time.js src/lib/automation-options.js ./src/lib/
+RUN mkdir /data && chown node:node /data
+USER node
+ENV PORT=3001 SYNC_HOST=0.0.0.0 SYNC_DB=/data/pardis.sqlite
+EXPOSE 3001
+HEALTHCHECK --interval=30s --timeout=5s --start-period=5s --retries=3 CMD node -e "fetch('http://127.0.0.1:3001/api/sync/health').then(r=>{if(!r.ok)process.exit(1)}).catch(()=>process.exit(1))"
+CMD ["node", "server/index.js"]