fix: Payment inference returns only exact-name matches when present

match_members() now short-circuits on whole-word full-name hits and
uses word-boundary regex everywhere else, so a nickname that is a
substring of another member's surname (e.g. "tov" inside "ottova")
no longer produces false positives. Adds tests/test_match_members.py.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

tests/test_match_members.py

@@ -0,0 +1,53 @@
+import unittest
+from scripts.match_payments import match_members
+
+
+MEMBERS = [
+    "Henrietta Ottová",
+    "Tomáš Němeček (Tov)",
+    "František Vrbík (Štrúdl)",
+    "Jana Nováková",
+]
+
+
+class TestMatchMembersExact(unittest.TestCase):
+    def test_full_name_in_message_returns_only_that_member(self):
+        # "tov" is a substring of "ottova" — the old code returned both members
+        result = match_members("Henrietta Ottová (Heny): 04/2026", MEMBERS)
+        names = [r[0] for r in result]
+        self.assertEqual(names, ["Henrietta Ottová"])
+        self.assertTrue(all(conf == "auto" for _, conf in result))
+
+    def test_nickname_tov_not_matched_inside_ottova(self):
+        # Bare nickname message should NOT match Tomáš via "tov" inside "ottova"
+        result = match_members("platba ottova 04/2026", MEMBERS)
+        names = [r[0] for r in result]
+        self.assertNotIn("Tomáš Němeček (Tov)", names)
+
+    def test_combined_payment_two_full_names(self):
+        result = match_members("Henrietta Ottová a Tomáš Němeček 04/2026", MEMBERS)
+        names = [r[0] for r in result]
+        self.assertIn("Henrietta Ottová", names)
+        self.assertIn("Tomáš Němeček (Tov)", names)
+        self.assertTrue(all(conf == "auto" for _, conf in result))
+
+    def test_nickname_alone_still_matches_correctly(self):
+        # "Tov" alone should still match Tomáš (as long as "ottova" is not in the text)
+        result = match_members("Tov platba 04/2026", MEMBERS)
+        names = [r[0] for r in result]
+        self.assertIn("Tomáš Němeček (Tov)", names)
+
+    def test_full_name_no_diacritics_still_matches(self):
+        result = match_members("Henrietta Ottova 04/2026", MEMBERS)
+        names = [r[0] for r in result]
+        self.assertIn("Henrietta Ottová", names)
+        self.assertNotIn("Tomáš Němeček (Tov)", names)
+
+    def test_first_last_name_present_any_order(self):
+        result = match_members("Platba od Nemeček Tomas 04/2026", MEMBERS)
+        names = [r[0] for r in result]
+        self.assertIn("Tomáš Němeček (Tov)", names)
+
+
+if __name__ == "__main__":
+    unittest.main()