Add instrument history helpers

crates/fidc-core/src/instrument.rs

@@ -39,6 +39,12 @@ impl Instrument {
         self.delisted_at
             .is_some_and(|delisted_at| delisted_at < date)
     }
+
+    pub fn is_active_on(&self, date: NaiveDate) -> bool {
+        self.listed_at.is_none_or(|listed_at| listed_at <= date)
+            && !self.is_delisted_before(date)
+            && !self.status.eq_ignore_ascii_case("inactive")
+    }
 }
 
 fn default_status() -> String {