修正回测出入金现金流中性口径

crates/fidc-core/tests/engine_hooks.rs

@@ -2648,6 +2648,13 @@ fn engine_applies_account_cash_flow_and_financing_intents() {
     assert!((result.equity_curve[0].total_equity - 10_458.0).abs() < 1e-6);
     assert!((result.equity_curve[1].cash - 12_416.0).abs() < 1e-6);
     assert!((result.equity_curve[1].total_equity - 11_416.0).abs() < 1e-6);
+    assert!((result.equity_curve[0].external_cash_flow - 500.0).abs() < 1e-6);
+    assert!((result.equity_curve[1].external_cash_flow - 1_000.0).abs() < 1e-6);
+    assert!((result.metrics.external_cash_flow_total - 1_500.0).abs() < 1e-6);
+    // The 1,500 external cash contribution must not be reported as a
+    // strategy return. Only the explicit management fee affects NAV here.
+    assert!(result.metrics.total_return < 0.0);
+    assert!(result.metrics.total_return > -0.01);
     assert!(result.account_events.iter().any(|event| {
         event
             .note