alibinhussain-star/FillForge ? reverse-engineered prompt

Build me a simple web app called FillForge that helps generate catalog template files from uploaded Excel dumps.

It should keep the existing footwear flow working, but also add a Consumer Electronics mode that I can switch to from the top bar. In CE mode, I want to upload a listing sample file, auto detect whether it is a Smart Phone or Feature Phone, and then generate the right catalog template for download.

Please make the app use the CE mapping template file from the project root, read the template sheets correctly, and support the CE specific rules like Child SKU, fixed set count, piece units, 18 percent GST, and the correct business category. The interface should have a clear sidebar for CE settings, a templates page with a CE download option, and a few basic help notes so it is easy to understand.

Keep it simple, working locally on port 5050, and use the existing Excel based workflow. If anything is unclear, look up the current docs online and make sensible choices.