test(nlp-service): guard global matcher state in try/finally

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

nlp-service/test_extractor.py

@@ -324,14 +324,12 @@ class TestExtract:
         # Should still find persons despite lowercase
         assert len(r.personNames) >= 1
 
-    def test_empty_matcher_returns_no_persons(self):
-        # Temporarily use an empty matcher
-        from extractor import set_person_matcher
-        empty = PersonMatcher()
-        set_person_matcher(empty)
-        r = extract("Briefe von Clara Cram", "de")
-        assert r.personNames == []
-        # Restore seeded matcher
-        m = PersonMatcher()
-        m.load(_TEST_PERSONS)
-        set_person_matcher(m)
+    def test_empty_matcher_returns_no_persons(self, seeded_matcher):
+        from extractor import get_person_matcher, set_person_matcher
+        original = get_person_matcher()
+        try:
+            set_person_matcher(PersonMatcher())
+            r = extract("Briefe von Clara Cram", "de")
+            assert r.personNames == []
+        finally:
+            set_person_matcher(original)