基本对象系统移植

src/heurams/kernel/particles/nucleon.py

@@ -0,0 +1,27 @@
+class Nucleon:
+    """核子: 材料元数据"""
+
+    def __init__(self, content: str, data: dict):
+        self.metadata = data
+        self.content = content
+
+    def __getitem__(self, key):
+        if key == "content":
+            return self.content
+        if key in self.metadata:
+            return self.metadata[key]
+        else:
+            raise KeyError(f"Key '{key}' not found in metadata.")
+
+    def __iter__(self):
+        yield from self.metadata.keys()
+
+    def __len__(self):
+        return len(self.metadata)
+
+    def __hash__(self):
+        return hash(self.content)
+
+    @staticmethod
+    def placeholder():
+        return Nucleon("核子对象样例内容", {})