SGrappelli/pronto ? reverse-engineered prompt

Build me a self hosted business app for a small salon or shop that handles booking, customer records, point of sale, and inventory in one place.

I want clients to book appointments online with just their name and phone number, then get reminder messages automatically by email and messaging apps. The owner should be able to see a calendar, drag appointments around, manage staff hours and breaks, and avoid double bookings. There should also be a simple CRM with client history, notes, tags, birthdays, and import from other booking tools.

For the shop side, make a fast checkout screen for services and products, support cash and card style payments, work offline as a PWA, and sync when internet comes back. Include product tracking with barcode support, stock counts, low stock alerts, and import and export for CSV or Excel. Also add multilingual support, a clean dashboard, and an easy way to turn modules on or off depending on whether it is a salon, cafe, or shop.

If you need to, look up current docs online while building it.