Change inits type from list to dict in ThinLayerCopasi

Updated the 'inits' attribute in the ThinLayerCopasi class from a list of InitMap to a dictionary mapping strings to InitMap. This change likely improves lookup efficiency and clarifies the intended data structure.

Author: JR-1991

pyenzyme/thinlayers/basico.py

@@ -45,7 +45,7 @@ class ThinLayerCopasi(BaseThinLayer):
 
     model: basico.COPASI.CDataModel
     model_dir: Path | str
-    inits: list[InitMap]
+    inits: dict[str, InitMap]
     cols: list[str]
     parameters: list
     nu_enzmldoc: v2.EnzymeMLDocument