feat: strategy builder

backend/routers/strategy_builder.py

@@ -282,6 +282,47 @@ def price(req: PriceRequest):
     result["spot"] = chain_slice["spot"]
     result["scenario_spot"] = surface_scenario.spot
     result["proxy"] = chain_slice["proxy"]
+
+    # Debug trace for two open questions (nominal/entry_cost not matching the UI's own bid/
+    # ask math, and "-∞" risk on structures that look bounded by hand): log EXACTLY what was
+    # received and computed, so both can be checked from System Logs (source=strategy_price_debug,
+    # or filter level=WARNING to jump straight to the unbounded cases) instead of digging
+    # through the browser's Network tab. Remove once both are confirmed resolved.
+    from services.database import log_system_event
+    bounded_risk = result.get("bounded_risk")
+    log_system_event(
+        level="INFO" if bounded_risk else "WARNING",
+        source="strategy_price_debug",
+        message=(
+            f"/price {req.scenario.symbol}: {len(legs)} jambe(s), nominal={req.scenario.contract_size}, "
+            f"entry_cost={result.get('entry_cost')} (mid={result.get('entry_cost_mid')}), "
+            f"broker_spread_cost={result.get('broker_spread_cost')}, "
+            f"max_gain={result.get('max_gain')}, max_loss={result.get('max_loss')}, bounded_risk={bounded_risk}"
+        ),
+        ticker=req.scenario.symbol,
+        details={
+            "legs_received": legs,
+            "scenario_received": {
+                "contract_size": req.scenario.contract_size,
+                "horizon_days": req.scenario.horizon_days,
+                "spot_shock_pct": req.scenario.spot_shock_pct,
+                "iv_level_shift": req.scenario.iv_level_shift,
+                "skew_tilt": req.scenario.skew_tilt,
+                "term_slope_shift": req.scenario.term_slope_shift,
+                "has_spot_path": bool(req.scenario.spot_path),
+                "has_iv_path": bool(req.scenario.iv_path),
+                "has_skew_path": bool(req.scenario.skew_path),
+                "has_term_path": bool(req.scenario.term_path),
+            },
+            "priced": {
+                "entry_cost": result.get("entry_cost"), "entry_cost_mid": result.get("entry_cost_mid"),
+                "broker_spread_cost": result.get("broker_spread_cost"),
+                "max_gain": result.get("max_gain"), "max_loss": result.get("max_loss"),
+                "bounded_risk": bounded_risk,
+            },
+            "risk_debug": result.get("risk_debug"),
+        },
+    )
     return result