Skip AppleDouble sidecars when listing a sysdiagnose (#922)

Device-generated sysdiagnose archives carry a ._name entry beside every
file that has extended attributes, an ACL or Finder info; one iOS 26
archive held 1234 of them among 3648 members, and the count grows with
each release. bsdtar folds them back into the file on extraction and
hides them from listings, but tarfile returns them as regular members,
so check-sysdiagnose extracted them and handed them to every module.
A module that globs for plists or logs then tries to parse AppleDouble
headers and logs one warning per sidecar.

Leave them out of the file list, both for archives and for folders
extracted on a system that keeps them as files.

src/mvt/ios/cmd_check_sysdiagnose.py

@@ -88,6 +88,8 @@ class CmdIOSCheckSysdiagnose(Command):
             parent_path = Path(self.target_path).absolute().parent
             for root, _, filenames in os.walk(self.target_path):
                 for filename in filenames:
+                    if filename.startswith("._"):
+                        continue
                     absolute_path = os.path.join(root, filename)
                     file_path = os.path.relpath(absolute_path, parent_path)
                     self.sysdiagnose_files.append(file_path)
@@ -137,6 +139,11 @@ class CmdIOSCheckSysdiagnose(Command):
 
             if not member_path.parts:
                 continue
+            # AppleDouble sidecars (._name) carry a file's extended attributes,
+            # not sysdiagnose content. Device archives hold hundreds of them;
+            # bsdtar hides them from listings, tarfile does not.
+            if member_path.name.startswith("._"):
+                continue
             archive_roots.add(member_path.parts[0])
 
             if member.isdir():

tests/test_cmd_check_sysdiagnose.py

@@ -34,6 +34,7 @@ def _create_sysdiagnose_folder(tmp_path):
         "sysdiagnose_2024.01.02_03-04-05+0200.tar.gz", encoding="utf-8"
     )
     (folder / "report.ips").write_text('{"bug_type": 210}\nbody', encoding="utf-8")
+    (folder / "._artifact.txt").write_bytes(b"\x00\x05\x16\x07AppleDouble")
     return folder
 
 
@@ -67,6 +68,7 @@ def test_check_sysdiagnose_from_folder(tmp_path):
     assert _test_module(command).ips_files == [
         {"file_path": str(tmp_path / "sysdiagnose" / "report.ips"), "bug_type": 210}
     ]
+    assert "sysdiagnose/._artifact.txt" not in command.sysdiagnose_files
 
 
 def test_check_sysdiagnose_from_archive_closes_archive(tmp_path):
@@ -83,6 +85,7 @@ def test_check_sysdiagnose_from_archive_closes_archive(tmp_path):
         }
     ]
     assert command.sysdiagnose_archive is None
+    assert "sysdiagnose/._artifact.txt" not in command.sysdiagnose_files
 
 
 def test_archive_is_extracted_once_and_unsafe_members_are_skipped(tmp_path):