feat: initialize standalone image-filter

Rename the distribution to image-filter and imports to image_filter.
Keep medical fixtures local and document their setup for fresh clones.
Include composite pipelines, consistent examples, and class diagrams.

tests/test_dimensions.py

@@ -0,0 +1,53 @@
+from __future__ import annotations
+
+import numpy as np
+import pytest
+
+from image_filter import (
+    DimensionInferenceError,
+    GaborFilter,
+    SliceWise,
+    UnsupportedDimensionError,
+    infer_spatial_layout,
+)
+
+
+def test_short_volume_or_rgb_without_metadata_is_ambiguous():
+    with pytest.raises(DimensionInferenceError, match="ambiguous"):
+        infer_spatial_layout(np.zeros((16, 17, 3)))
+    assert infer_spatial_layout(np.zeros((16, 17, 3)), {"spatial_dims": 3}).dimension == 3
+
+
+def test_4d_requires_channel_axis():
+    image = np.zeros((8, 9, 10, 2))
+    with pytest.raises(DimensionInferenceError, match="requires"):
+        infer_spatial_layout(image)
+    assert infer_spatial_layout(image, {"channel_axis": 3}).dimension == 3
+
+
+def test_intrinsically_2d_filter_rejects_volume_in_strict_mode():
+    with pytest.raises(UnsupportedDimensionError, match="SliceWise"):
+        GaborFilter().apply(np.ones((6, 7, 8)), {"spatial_dims": 3})
+
+
+def test_slice_wise_is_explicit_and_axis_sensitive():
+    image = np.zeros((4, 12, 13), dtype=np.float32)
+    image[:, 5, :] = 1
+    adapter = SliceWise(GaborFilter(frequency=0.2), axis=0)
+    result = adapter.apply(image)
+    from skimage.filters import gabor
+    expected = np.stack([np.hypot(*gabor(plane.astype(np.float64), frequency=.2, sigma_x=2, sigma_y=2)) for plane in image])
+    np.testing.assert_allclose(result.image, expected)
+    assert result.image.shape == image.shape
+    assert result.image.dtype == np.float64
+    assert np.isfinite(result.image).all()
+    assert result.metadata["processing_history"][-1]["filter"] == "SliceWise"
+    nested = result.metadata["processing_history"][-1]["parameters"]["filter"]
+    assert nested["filter"] == "GaborFilter"
+    assert nested["parameters"]["frequency"] == 0.2
+
+
+def test_slice_wise_rejects_non_spatial_axis():
+    image = np.ones((5, 6, 7, 3))
+    with pytest.raises(UnsupportedDimensionError, match="spatial axes"):
+        SliceWise(GaborFilter(), axis=3).apply(image, {"channel_axis": 3})