Offline Windows Restaurant POS with Inventory

I run a small restaurant and need a lightweight, fully offline POS that runs on Windows. The essentials are straightforward:

• Order processing – dine-in and takeaway tickets should be quick to enter, edit and close.
• Payment processing – cash and card totals captured at checkout with simple daily summaries.
• Inventory management – every menu item should reduce stock automatically so I can see current levels and low-stock alerts without going online.

No user hierarchy is required; a single login is fine. A clean, touch-friendly interface would be a plus, but speed and stability come first since this machine is never connected to the internet.

Deliverables
1. Windows installer (or portable EXE) ready to use on one PC.
2. Source code so I can extend the system later.
3. A concise setup & user guide that shows how to add menu items, record sales, and update inventory.

If you have a proven framework or past demo that fits these needs, let me see it and we can move forward quickly.