Add limit price slippage support

crates/fidc-core/tests/explicit_order_flow.rs

@@ -2802,6 +2802,43 @@ fn broker_keeps_limit_buy_open_until_price_becomes_marketable() {
     );
 }
 
+#[test]
+fn broker_uses_limit_price_slippage_for_limit_orders() {
+    let date = NaiveDate::from_ymd_opt(2024, 1, 10).unwrap();
+    let data = two_day_limit_order_data(10.0, 10.0);
+    let broker = BrokerSimulator::new_with_execution_price(
+        ChinaAShareCostModel::default(),
+        ChinaEquityRuleHooks::default(),
+        PriceField::Open,
+    )
+    .with_slippage_model(SlippageModel::LimitPrice);
+    let mut portfolio = PortfolioState::new(1_000_000.0);
+
+    let report = broker
+        .execute(
+            date,
+            &mut portfolio,
+            &data,
+            &StrategyDecision {
+                rebalance: false,
+                target_weights: BTreeMap::new(),
+                exit_symbols: BTreeSet::new(),
+                order_intents: vec![OrderIntent::LimitShares {
+                    symbol: "000002.SZ".to_string(),
+                    quantity: 200,
+                    limit_price: 10.1,
+                    reason: "limit_entry".to_string(),
+                }],
+                notes: Vec::new(),
+                diagnostics: Vec::new(),
+            },
+        )
+        .expect("broker execution");
+
+    assert_eq!(report.fill_events.len(), 1);
+    assert!((report.fill_events[0].price - 10.1).abs() < 1e-9);
+}
+
 #[test]
 fn broker_cancels_open_order_by_order_id() {
     let day1 = NaiveDate::from_ymd_opt(2024, 1, 10).unwrap();