feat: recalbox 346/346 via md5_composite, add mame variants

Add md5_composite() to verify.py replicating Recalbox Zip::Md5Composite
(sorted filenames, sequential content hash). Independent of ZIP
compression level, resolves all 9 MAME arcade untested entries.

Add Recalbox-specific MAME ZIP variants from Recalbox 10 pack.
Batocera 671/680 (9 untested MAME-specific), all others 100%.

scripts/common.py

@@ -54,6 +54,21 @@ def md5sum(filepath: str | Path) -> str:
     return h.hexdigest()
 
 
+def md5_composite(filepath: str | Path) -> str:
+    """Compute composite MD5 of a ZIP - matches Recalbox's Zip::Md5Composite().
+
+    Sorts filenames alphabetically, reads each file's contents in order,
+    feeds everything into a single MD5 hasher. The result is independent
+    of ZIP compression level or metadata.
+    """
+    with zipfile.ZipFile(filepath) as zf:
+        names = sorted(n for n in zf.namelist() if not n.endswith("/"))
+        h = hashlib.md5()
+        for name in names:
+            h.update(zf.read(name))
+        return h.hexdigest()
+
+
 def load_platform_config(platform_name: str, platforms_dir: str = "platforms") -> dict:
     """Load a platform config with inheritance and shared group resolution.