feat: avoid copies when constructing self

Signed-off-by: nstarman <[email protected]>

src/vector/_base.py

@@ -582,6 +582,10 @@ def constructor(  # noqa: D417
         msg = f"Cannot construct {cls} from {type(obj)}."
         raise TypeError(msg)
 
+    # avoid copying if the types are the same
+    if type(obj) is cls:
+        return obj
+
     return cls(**dict(dataclass_items(obj)))