Multi-Company Inventory & Staff Suite

I need a single software package that can be rolled out across four sister companies, handling both inventory and human-resource oversight from one dashboard.

Inventory module
The system must let me monitor stock levels in real time, raise and fulfil purchase or sales orders, and keep supplier data at hand. Low-stock alerts, order status updates, and a clear audit trail for every item moving in or out of any of the four businesses are non-negotiable.

Staff module
For every employee I want a daily activity log, GPS-based location capture when they clock in or change job sites, and an easy way to record periodic performance notes that managers can later review. All data should be filterable by company, department, and individual.

General requirements
• One login should let me switch between the four companies without logging out.
• Clean, modern web interface—mobile responsiveness is important because supervisors will access it from phones on the warehouse floor.
• Role-based permissions so warehouse staff, managers, and execs each see only what they need.
• No external integrations are required right now; the system can run entirely stand-alone.
• Source code and a brief technical handover (database schema, setup guide) complete the delivery.

Acceptance criteria
The build is considered complete when I can:
1. Create products, suppliers, and stock locations for all four companies.
2. Generate and track an end-to-end purchase order through to receipt and stock update.
3. View a live head-count map showing which employees are on-site or off-site.
4. Pull a weekly performance report per employee in PDF or Excel.

If you have previously implemented similar ERP, inventory, or HRM solutions—especially multi-tenant ones—please mention it when you reply and outline the tech stack you propose.