VishnuArrawatia/gst-software ? reverse-engineered prompt

Build me a standalone GST control app for our office that helps reconcile purchase invoices against GSTR 2B and prepare GSTR 3B and GSTR 1 from our sales register.

I want a simple local web app where someone can drop the monthly files into one folder, upload them, run the reconciliation, and then see clear results like missing in 2B, amount mismatches, blocked ITC, duplicates, and invoices that are in 2B but not booked. It should also keep a running ITC balance, show the lapse deadline, and generate a clean Excel report with separate sheets plus portal ready JSON files for GSTR 1 and GSTR 3B.

Make it work for multiple GSTINs and monthly periods, with a browser based workflow for the team on the office network. If useful, add a password option for the web page, and make sure the same logic works from both the web app and a command line run. If you need to, look up the current GST portal formats online.