Replace Node BE with PouchDB IndexedDB API | Push notifications PWA

There is already a web version of the app live which sends user scheduled push notifications from the browser with the browser native JavaScript Notification API, but when the webserver needs a restart, all is reset as all is stored only in the memory. So, your task is to create and set up the backend using PouchDB, IndexedDB API, Notification API, and Vibration API. The Progressive Web App is built in pure Vanilla JavaScript, not using any framework (no React, no Vue, no Angular, etc.). It shall only use pure JS web components, custom elements, and plain CSS, no SASS. Acceptance criteria: 1. User can click calendar events in PWA (Chrome on a mobile device), turn off the device, and still get notified continuously the following days on set scheduled notifications. No login is required. 2. User shall be able to do as in #1 even with the latest Android native web browser. 3. User shall be able to do as in #1 even on a PC with the latest Chrome browser and get notifications continuously the following days on set scheduled notifications when the browser is re-opened. 4. The user shall be able to set (with a button in UI) if notifications also shall give vibration, sound, or be silent with no vibration. Vibration API OK if it only works in Firefox. 5. Toggle checkboxes shall not be reset on browser refresh or device restart. IndexedDB API inspiration: [login to view URL]