Loads dummy-fulldata.csv (lot, wafer, x, y, hbin, sbin, test columns) and maps each row to a DieResult. Select a wafer from the dropdown — the map re-renders instantly. Metadata about the CSV file appears in the sidebar. Each die carries a siteId metadata field — the prober sequence index from the CSV, assigned in a snake pattern (LL corner, alternating column direction). Hover any die to see it in the tooltip. The toolbar notebook icon opens the built-in summary panel showing yield, bin breakdown, and wafer-level custom metadata.