fix: replace editdistance with rapidfuzz for python 3.13 wheel support (#18132)

### Summary

Fixes #18107.

`editdistance==0.8.1` (the only recent release on PyPI) has no cp313
wheels for any platform. Since this project requires exactly Python
3.13, `uv`/`pip`/`poetry` fall back to building it from source (Cython),
which fails on Windows for anyone without a working C build toolchain —
that's the PEP 517 build error in the issue.

Swapped `editdistance` for `rapidfuzz`, which ships full cp313 wheels
(win32/win_amd64/win_arm64 included) and has no build-from-source step
on any of our target platforms. The only call site was
`EntityResolution.is_similarity` in `rag/graphrag/entity_resolution.py`,
using `editdistance.eval(a, b)` to get the unweighted Levenshtein
distance between two entity names.
`rapidfuzz.distance.Levenshtein.distance(a, b)` computes the same thing
(verified identical output on several string pairs) and is used as a
direct replacement.

test/unit_test/rag/graphrag/test_entity_resolution.py

@@ -0,0 +1,34 @@
+#
+#  Copyright 2026 The InfiniFlow Authors. All Rights Reserved.
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+#
+
+from rag.graphrag.entity_resolution import EntityResolution
+
+
+def _resolver():
+    return EntityResolution(llm_invoker=None)
+
+
+def test_is_similarity_matches_within_half_edit_distance():
+    resolver = _resolver()
+
+    assert resolver.is_similarity("microsoft", "microsfot") is True
+    assert resolver.is_similarity("apple", "orange") is False
+
+
+def test_is_similarity_identical_strings():
+    resolver = _resolver()
+
+    assert resolver.is_similarity("openai", "openai") is True