refact: add cargo "python" feature for pyo3

store/src/lib.rs

@@ -20,6 +20,7 @@ pub use dice::{Dice, DiceRoller};
 pub mod training_common;
 
 // python interface "trictrac_engine" (for AI training..)
+#[cfg(feature = "python")]
 mod pyengine;
 
 // C++ interface via cxx.rs (for OpenSpiel C++ integration)

store/src/player.rs

@@ -1,3 +1,4 @@
+#[cfg(feature = "python")]
 use pyo3::prelude::*;
 use serde::{Deserialize, Serialize};
 use std::fmt;
@@ -5,7 +6,7 @@ use std::fmt;
 // This just makes it easier to dissern between a player id and any ol' u64
 pub type PlayerId = u64;
 
-#[pyclass(eq, eq_int)]
+#[cfg_attr(feature = "python", pyclass(eq, eq_int))]
 #[derive(Copy, Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 pub enum Color {
     White,