fix: a hashless entry is a path in any mode

Whether the frontend compares content was decided per platform. EmuDeck
(md5) declares neocdz.zip with no hash and checkBIOS.sh never names it,
yet the proven claims of geolith and FBNeo were dropped and the pack
shipped a neocdz.zip without 000-lo.lo. checked_by_path() decides per
entry: no hash of the kind the frontend compares (any of md5, sha1,
crc32 under RomM's rule) and no zipped_file means a path. Measured: the
EmuDeck neocdz.zip slot and three RetroBat DS slots (dsi_bios7.bin,
dsi_bios9.bin, firmware.bin) now take the file the cores prove.

tests/test_slots.py

@@ -349,6 +349,7 @@ class TestArbitration(unittest.TestCase):
     def _conflict(self):
         platform = slots.Claim(
             "platform", "GC/JAP/IPL.bin", "IPL.bin",
+            entry={"md5": "m" * 32, "sha1": "a" * 40},
             local_path="bios/Console/GC/USA/IPL.bin", status="md5_exact",
         )
         profile = slots.Claim(
@@ -376,6 +377,40 @@ class TestArbitration(unittest.TestCase):
         self.assertEqual(decision.winner.origin, "profile")
         self.assertFalse(decision.serves_both)
 
+    def test_a_hashless_entry_is_a_path_in_an_md5_platform(self):
+        """EmuDeck declares neocdz.zip with no md5 and checkBIOS.sh never
+        names it: the frontend checks nothing there, so the core's file
+        serves both."""
+        conflict = self._conflict()
+        conflict.platform_claim.entry = {"name": "IPL.bin"}
+        for mode in ("md5", "sha1"):
+            with self.subTest(mode=mode):
+                self.assertTrue(slots.arbitrate(conflict, mode).serves_both)
+        # RomM compares size then any hash: a hash of another kind is content.
+        conflict.platform_claim.entry = {"name": "IPL.bin", "sha1": "a" * 40, "size": 3}
+        self.assertFalse(
+            slots.arbitrate(conflict, "md5", rule="size_and_any_hash").serves_both
+        )
+        conflict.platform_claim.entry = {"name": "x.zip", "zipped_file": "IPL.bin"}
+        self.assertFalse(slots.arbitrate(conflict, "md5").serves_both)
+
+    def test_the_pack_serves_the_proven_file_at_a_hashless_md5_entry(self):
+        config = {
+            "verification_mode": "md5",
+            "cores": ["dolphin"],
+            "systems": {"console": {"files": [
+                {"name": "IPL.bin", "destination": "IPL.bin"},
+                {"name": "IPL.bin", "destination": "hashed/IPL.bin", "md5": "m" * 32},
+            ]}},
+        }
+        profiles = {"dolphin": {"type": "libretro", "systems": ["console"], "files": [
+            {"name": "IPL.bin", "md5": "n" * 32},
+            {"name": "IPL.bin", "path": "hashed/IPL.bin", "md5": "n" * 32},
+        ]}}
+        overrides = slots.pack_overrides(config, profiles, REGIONS_DB)
+        # The hashed declaration keeps the file the frontend checks.
+        self.assertEqual(overrides, {"IPL.bin": "bios/Console/GC/JAP/IPL.bin"})
+
     def test_the_reported_line_gives_the_ground_for_the_decision(self):
         kept = slots.format_decision(slots.arbitrate(self._conflict(), "md5"))
         self.assertIn("verifies content", kept)