Coupled ρ Dynamics — cross-centre tightness

Three centres can each look manageable while the SYSTEM tightens — the coupling is the story. This operator moves only the cross-centre edges, from observable legs, and reads the coupled rho as a monthly dual read.

How it reads

coupled_rho_path[] with the dual read; today_decomposition names the cross-centre leg doing the work. Baseline rules follow the Fisher-Rao calmest-window convention.