fix:Address type annotation and linting issues

Author: mkitti

src/zarr/core/indexing.py

@@ -1667,7 +1667,7 @@ def _morton_order(chunk_shape: tuple[int, ...]) -> tuple[tuple[int, ...], ...]:
             # Compute Morton order on squeezed shape
             squeezed_order = _morton_order(squeezed_shape)
             # Expand coordinates to include singleton dimensions (always 0)
-            order: list[tuple[int, ...]] = []
+            expanded: list[tuple[int, ...]] = []
             for coord in squeezed_order:
                 full_coord: list[int] = []
                 squeezed_idx = 0
@@ -1677,8 +1677,8 @@ def _morton_order(chunk_shape: tuple[int, ...]) -> tuple[tuple[int, ...], ...]:
                     else:
                         full_coord.append(coord[squeezed_idx])
                         squeezed_idx += 1
-                order.append(tuple(full_coord))
-            return tuple(order)
+                expanded.append(tuple(full_coord))
+            return tuple(expanded)
         else:
             # All dimensions are singletons, just return the single point
             return ((0,) * len(chunk_shape),)
@@ -1696,10 +1696,11 @@ def _morton_order(chunk_shape: tuple[int, ...]) -> tuple[tuple[int, ...], ...]:
         n_hypercube = 0
 
     # Within the hypercube, no bounds checking needed - use vectorized decoding
+    order: list[tuple[int, ...]]
     if n_hypercube > 0:
         z_values = np.arange(n_hypercube, dtype=np.intp)
         hypercube_coords = decode_morton_vectorized(z_values, chunk_shape)
-        order: list[tuple[int, ...]] = [tuple(row) for row in hypercube_coords]
+        order = [tuple(row) for row in hypercube_coords]
     else:
         order = []