v21.0 Extended Backtest and Walk-Forward Testing

Period: 2020-01-01 to 2026-06-04 Total Days: 2347 Previous Backtest: 186 days (2025-12-01 to 2026-06-04) Extended Range: +2.5 years back to 2020-01-01

I. Extended Coverage Metrics

| Metric | Extended (2020-2026) | Previous (186d) | Change | |--------|---------------------|-----