E-Commerce & Admin Inventory Portal

I need an e-commerce website that comes with a robust back-office so I can run both sales and day-to-day operations from one place. The public-facing side should handle typical online-store features—product catalog, cart, checkout, payment integration—while a private admin panel (protected by secure login) lets me:

• Track and update inventory in real time
• Store and edit worker details (roles, contact, hiring date, etc.)
• Calculate and record salaries, with the option to export payroll data

Clean code, responsive design, and clear documentation are must-haves because the site will grow with my business. If you can set it up so I can add future modules easily, even better.