Support Python 3.11 isolated restore

Assistant: codex
Assistant-Model: gpt-5.6-sol
Assistant-Session: 01a02994-7685-7940-bf34-3555b8256018

scripts/s1_restore.py

@@ -210,7 +210,13 @@ def extract_bundle(
             expected = validated["manifest"]["os_config_members"]
             if observed != expected:
                 raise RestoreError("decrypted archive membership or modes differ from manifest")
-            archive.extractall(path=stage, filter="data")
+            # Python 3.12 added the extraction filter argument. On older
+            # supported runtimes the complete member/link/type validation
+            # above is the equivalent fail-closed gate before extraction.
+            if sys.version_info >= (3, 12):
+                archive.extractall(path=stage, filter="data")
+            else:
+                archive.extractall(path=stage)
         plain_archive.unlink()
         packages = stage / "packages.txt"
         _decrypt(executable, identity, artifacts["packages"], packages)