fix: include juniors in payment-inference roster

infer_payments was building member_names from get_members_with_fees()
(adults sheet only). Junior-only members were invisible to the matcher,
so a payment message containing an exact junior name would produce a
fuzzy review match against a different adult sharing the same first name.

Fix: union the adult and junior rosters (deduped via canonical_member_key)
so all members are candidates. The existing exact-name short-circuit in
match_members then handles precedence correctly.

Two regression tests added for the Jáchym Kubík / Jáchym Hrušák case.

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

tests/test_match_members.py

@@ -48,6 +48,25 @@ class TestMatchMembersExact(unittest.TestCase):
         names = [r[0] for r in result]
         self.assertIn("Tomáš Němeček (Tov)", names)
 
+    def test_shared_first_name_junior_in_roster_wins_exact(self):
+        # Regression: two members share first name "Jáchym"; message has full name
+        # of the junior-only member → exact match must win, no [?] on the adult.
+        roster = ["Jáchym Hrušák (G)", "Jáchym Kubík"]
+        result = match_members(
+            "JIŘÍ KUBÍK Jáchym Kubík: 01/2026+03/2026+04/2026", roster
+        )
+        self.assertEqual(result, [("Jáchym Kubík", "auto")])
+
+    def test_shared_first_name_without_junior_in_roster_falls_back(self):
+        # Without Kubík in the roster (old behaviour), Hrušák wins via first-name
+        # partial match — confirms the roster-expansion fix is the real solution.
+        roster = ["Jáchym Hrušák (G)"]
+        result = match_members(
+            "JIŘÍ KUBÍK Jáchym Kubík: 01/2026+03/2026+04/2026", roster
+        )
+        names = [r[0] for r in result]
+        self.assertIn("Jáchym Hrušák (G)", names)
+
 
 if __name__ == "__main__":
     unittest.main()