Remove unused imports and variables (pyflakes)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: constantinpape

src/bioimage_cpp/label_multiset/__init__.py

@@ -22,7 +22,7 @@
 from __future__ import annotations
 
 from dataclasses import dataclass
-from typing import Optional, Tuple, Union
+from typing import Tuple
 
 import numpy as np
 

tests/graph/test_rag_lifted_features.py

@@ -219,7 +219,6 @@ def test_lifted_affinity_features_skips_local_hits():
         ],
         dtype=np.uint32,
     )
-    rag = bic.graph.region_adjacency_graph(labels)
     # Offset (2, 2): in a 3x3 grid only (0, 0) -> (2, 2), both label 0.
     # So no diff, no accumulation. We pass a lifted edge that doesn't exist
     # in the data to make sure no accumulation happens.

tests/label_multiset/test_merger.py

@@ -1,9 +1,7 @@
 import numpy as np
 
-from bioimage_cpp._core import Blocking
 from bioimage_cpp.label_multiset import (
     MultisetMerger,
-    downsample_multiset,
     multiset_from_labels,
 )
 

tests/label_multiset/test_read_subset.py

@@ -1,5 +1,4 @@
 import numpy as np
-import pytest
 
 from bioimage_cpp.label_multiset import read_subset