The Dashboard
A dashboard over a database of orders that lives inside this browser tab. Pick how many rows, build it, then click any chart: every other panel re-asks the database, and the page shows what each question cost on your device. No server, no upload.
The Dashboard runs on your own device, inside this tab. Starting it downloads the .NET runtime that does the work (about 11 MB the first time); your browser keeps it for next time.
This runs on HoloDb, the embeddable .NET SQL engine, compiled to WebAssembly. The totals and the region, category, status and month panels are answered by its Pleroma aggregate plane; the top customers and the largest orders are answered by its column scans. Each panel is tagged with the route HoloDb reported and the time this tab measured. The table is generated here from a fixed seed, so a console app that runs the code above builds the same rows.