feat: better state_handler

diceplayer/config/dice_config.py

@@ -1,4 +1,4 @@
-from pydantic import BaseModel, Field
+from pydantic import BaseModel, Field, ConfigDict
 from typing_extensions import List, Literal
 
 
@@ -6,6 +6,9 @@ class DiceConfig(BaseModel):
     """
     Data Transfer Object for the Dice configuration.
     """
+    model_config = ConfigDict(
+        frozen=True,
+    )
 
     ljname: str = Field(..., description="Name of the Lennard-Jones potential file")
     outname: str = Field(