docs: record nonrotating larger-window validation

experiments/KRYLOV_WINDOW_HYPOTHESIS_2026-09-16.md

@@ -34,6 +34,10 @@ of critical rotation and does not alter the convergence or virial tolerances.
 
 Removing the n=1 example's central-density constraint is independently supported
 on `research/central-constraint-20260916`; combine the two changes for the intended
-example. Compilation and a nonrotating run of the combined example are pending.
+example. The combined sandbox compiles at `b3a752b`. Its nonrotating physical
+counterpart in the diagnostic at `c88baa1` reaches strict convergence in six
+full steps, with F=1.65157e-13 and all eight q14/q18 virial checks below
+3.731e-7. The diagnostic uses its recorded stopping controls; this is not a
+claim that the literal sandbox executable was used for the physical measurements.
 Raw results and exact build/mesh/executable provenance are retained in the
 workspace's `diagnostics/numerical_campaign_2026-09-16/controls` directory.