fix: keep release profiles on the build they pin

mame_hash_scraper --release rewrote the whole profile and dropped the
pin_frozen that mame0258 and mame0278 carry: libretro/mame HEAD is a
later release, so without it profile_sync compares their refs with code
the Recalbox build never had. A release profile now states it, from
built_by, and keeps the reason a reader wrote.

scripts/scraper/mame_hash_scraper.py

@@ -470,6 +470,13 @@ def release_profile(
         "display_name": f"Arcade (MAME {version})",
         "cores": cores,
         "built_by": built_by,
+        # The pin is the commit the platform builds, so the profile is judged
+        # against its own revision: libretro/mame HEAD is a later release.
+        "pin_frozen": (
+            f"{', '.join(built_by)} build{'s' if len(built_by) == 1 else ''} "
+            f"libretro/mame at this revision for the {version} release. "
+            "Later commits are not part of that build."
+        ),
         "systems": list(reference.get("systems") or []),
         "notes": (
             f"libretro/mame built at the {version} release. BIOS root sets "
@@ -498,6 +505,12 @@ def _write_release(args: argparse.Namespace) -> None:
         args.release, bios_sets, commit, args.source_commit, args.core, reference,
         args.built_by,
     )
+    # A reason a reader wrote, citing the platform's own build file, outlives
+    # a regeneration: the derived one says less.
+    if Path(args.profile).is_file():
+        previous = yaml_load(Path(args.profile).read_text(encoding="utf-8")) or {}
+        if str(previous.get("pin_frozen") or "").strip():
+            profile["pin_frozen"] = previous["pin_frozen"]
     text = yaml.safe_dump(profile, sort_keys=False, allow_unicode=True, width=100)
     # Citations are written double-quoted in every profile: left bare, each
     # regeneration rewrote all of them.

tests/test_hash_merge.py

@@ -478,6 +478,9 @@ class AReleaseProfileDescribesItsOwnRelease(unittest.TestCase):
                          ("a" * 40, "b" * 40))
         self.assertEqual(profile["cores"], ["mame0278"])
         self.assertEqual(profile["built_by"], ["recalbox"])
+        # libretro/mame HEAD is a later release: the profile is judged
+        # against the revision the platform builds.
+        self.assertIn("recalbox builds libretro/mame", profile["pin_frozen"])
         files = {f["name"]: f for f in profile["files"]}
         self.assertEqual(sorted(files), ["neogeo.zip", "newset.zip"])
         self.assertEqual(files["neogeo.zip"]["system"], "snk-neogeo-mvs")