Pin the parenthesized members pattern to a single split point

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

tools/src/pop_fem_audit_tools/commands/build_db.py

@@ -247,7 +247,7 @@ class ArtistImporter:
     """The pattern separating a group prefix from its members in a
     "<group>: <members>" credit."""
     PAREN_MEMBERS_PATTERN: re.Pattern[str] = re.compile(
-        r"^.+ \((?P<members>.+)\)$")
+        r"^[^(]+ \((?P<members>[^()]+)\)$")
     """The pattern separating a group name from its members in a
     "<group> (<members>)" credit spanning the whole credit."""
     DUET_WITH_PATTERN: re.Pattern[str] = re.compile(