- NaN composite score: dropna().mean() on empty series returns NaN,
nan is truthy so (nan or 0)=nan. Fixed: use None when no MFE data
so scorer uses 0.5 fallback instead of propagating NaN.
- Analysis stopping: gate WFV was importing from main.execute_run
(old CLI code that uses broken runner). Fixed: gate.run_walk_forward
now accepts an executor callable from optimizer_loop.
- Back to Dashboard opened blank tab: Reports button used
window.open(_blank). Fixed: same-tab navigation + history.back().
- NaN in reports card: downstream of composite_score NaN above.