fix: file the SF-7000 rom under Sega

sf7000.rom is read only by the sega-sf7000 entries of blueMSX. It sat in bios/Microsoft/MSX because blueMSX keeps its machine folders together, which is a pack destination, not where the collection files a dump.

tests/test_sega_filing.py

@@ -0,0 +1,49 @@
+"""Sega ROMs live under bios/Sega.
+
+The SF-7000 disk unit ROM, which only the sega-sf7000 entries read, sat in
+bios/Microsoft/MSX because blueMSX keeps its machine folders together. The
+collection files a dump under the maker of the machine it belongs to, and
+the blueMSX layout is a destination the pack writes, not a storage rule.
+Reads the repository.
+"""
+
+from __future__ import annotations
+
+import sys
+import unittest
+from pathlib import Path
+
+REPO_ROOT = Path(__file__).resolve().parents[1]
+sys.path.insert(0, str(REPO_ROOT / "scripts"))
+
+
+class SegaFilesStayUnderSega(unittest.TestCase):
+    def test_no_sega_only_file_under_msx(self):
+        folder = REPO_ROOT / "bios" / "Microsoft" / "MSX"
+        if not folder.is_dir():
+            self.skipTest("bios/Microsoft/MSX is absent")
+        from common import load_emulator_profiles
+
+        systems: dict[str, set[str]] = {}
+        for profile in load_emulator_profiles(str(REPO_ROOT / "emulators")).values():
+            for entry in profile.get("files") or []:
+                if not isinstance(entry, dict) or not entry.get("system"):
+                    continue
+                for name in [entry.get("name", ""), *(entry.get("aliases") or [])]:
+                    key = Path(str(name)).name.lower()
+                    systems.setdefault(key, set()).add(str(entry["system"]))
+        misfiled = sorted(
+            str(path.relative_to(folder))
+            for path in folder.rglob("*")
+            if path.is_file()
+            and systems.get(path.name.lower())
+            and all(s.startswith("sega-") for s in systems[path.name.lower()])
+        )
+        self.assertEqual(misfiled, [])
+
+    def test_sf7000_rom_is_filed_under_sega(self):
+        self.assertTrue((REPO_ROOT / "bios" / "Sega" / "SF-7000" / "sf7000.rom").is_file())
+
+
+if __name__ == "__main__":
+    unittest.main()