fix: map bizhawk's ares to its n64 core only

BizHawk embeds ares as Ares64, its N64 core, whose 64DD IPL its own
FirmwareDatabase declares. Mapped to the whole ares profile, it pulled
thirty systems into the BizHawk pack and made slots accuse
FirmwareDatabase.cs of a wrong MSX.rom it never declared for ares.

tests/test_scraper_contract.py

@@ -331,6 +331,21 @@ class RetroDeckCoresAreItsComponents(unittest.TestCase):
         self.assertNotIn("cores", registry["platforms"]["retrodeck"])
 
 
+class BizHawkRunsAresForN64Only(unittest.TestCase):
+    """BizHawk embeds ares as Ares64, its N64 core; mapping it to the ares
+    profile claimed thirty systems and accused FirmwareDatabase.cs of a
+    wrong MSX.rom it never declared for ares."""
+
+    def test_ares_is_not_a_bizhawk_core(self):
+        import yaml
+
+        root = Path(__file__).resolve().parents[1]
+        platform = yaml.safe_load((root / "platforms" / "bizhawk.yml").read_text())
+        registry = yaml.safe_load((root / "platforms" / "_registry.yml").read_text())
+        self.assertNotIn("ares", platform["cores"])
+        self.assertNotIn("ares", registry["platforms"]["bizhawk"]["cores"])
+
+
 class UnreadableReleaseStopsTheScrape(unittest.TestCase):
     """A failed tag lookup fell back to master, or to an empty or invented
     version. BizHawk, RomM, Batocera and Recalbox then wrote a YAML read from