Slice window start

Stored window.from on the OpenRouter slice file. The label is from. The value is the stored date 2026-04-27. The same window stores through 2026-10-27. The bar is full when a start date is stored. The bar is not a score. This is the benchmark slice window start, not the rankings file start, not the rankings window start, and not the app board start. A missing start date stays off the page.