Add management fee callbacks

crates/fidc-core/src/strategy.rs

@@ -17,6 +17,13 @@ use crate::universe::{DynamicMarketCapBandSelector, SelectionContext, UniverseSe
 
 pub trait Strategy {
     fn name(&self) -> &str;
+    fn management_fee(
+        &mut self,
+        _ctx: &StrategyContext<'_>,
+        _rate: f64,
+    ) -> Result<Option<f64>, BacktestError> {
+        Ok(None)
+    }
     fn on_process_event(
         &mut self,
         _ctx: &StrategyContext<'_>,
@@ -115,6 +122,8 @@ pub struct PortfolioRuntimeView {
     pub trading_pnl: f64,
     pub position_pnl: f64,
     pub cash_liabilities: f64,
+    pub management_fee_rate: f64,
+    pub management_fees: f64,
 }
 
 pub struct StrategyContext<'a> {
@@ -368,6 +377,8 @@ impl StrategyContext<'_> {
             trading_pnl: self.portfolio.trading_pnl(),
             position_pnl: self.portfolio.position_pnl(),
             cash_liabilities: self.portfolio.cash_liabilities(),
+            management_fee_rate: self.portfolio.management_fee_rate(),
+            management_fees: self.portfolio.management_fees(),
         }
     }
 
@@ -819,6 +830,10 @@ pub enum OrderIntent {
         amount: f64,
         reason: String,
     },
+    SetManagementFeeRate {
+        rate: f64,
+        reason: String,
+    },
 }
 
 #[derive(Debug, Clone)]