Tighten qualified signal gate

frontend/src/lib/qualification.ts

@@ -39,13 +39,15 @@ export function qualifiesSetup(setup: TradeSetup, config: ActivationConfig): boo
   if (setup.current_price != null && liveRiskReward(setup, setup.current_price) < config.min_rr) {
     return false;
   }
+  const targetProbability = primaryTargetProbability(setup);
+  if (targetProbability == null || targetProbability <= 0) return false;
   if ((setup.confidence_score ?? 0) < config.min_confidence) return false;
   // Residual cross-sectional momentum is the core selection (long-only). While
-  // the gate is active, shorts never qualify; the percentile floor is enforced
-  // only when a percentile is attached, otherwise defer to the floors.
+  // the gate is active, shorts never qualify; missing ranks do not qualify
+  // because the production edge depends on this cross-sectional selection.
   if (config.min_momentum_percentile > 0) {
     if (setup.direction === 'short') return false;
-    if (setup.momentum_percentile != null && setup.momentum_percentile < config.min_momentum_percentile) {
+    if (setup.momentum_percentile == null || setup.momentum_percentile < config.min_momentum_percentile) {
       return false;
     }
   }