Rename some filers and folder for clarity

src/backend/models/model_item.py

@@ -0,0 +1,33 @@
+from typing import Any, Dict, Optional
+
+from ..utils import serialize_value_for_qml
+
+
+class ModelItem:
+    def __new__(cls, *_args, **_kwargs) -> "ModelItem":
+        from .model import Model
+        cls.parent_model: Optional[Model] = None
+        return super().__new__(cls)
+
+
+    def __setattr__(self, name: str, value) -> None:
+        super().__setattr__(name, value)
+
+        if name != "parent_model" and self.parent_model is not None:
+            with self.parent_model._sync_lock:
+                self.parent_model._changed = True
+
+
+    def __delattr__(self, name: str) -> None:
+        raise NotImplementedError()
+
+
+    @property
+    def serialized(self) -> Dict[str, Any]:
+        return {
+            name: serialize_value_for_qml(getattr(self, name))
+            for name in dir(self)
+            if not (
+                name.startswith("_") or name in ("parent_model", "serialized")
+            )
+        }