Run staged Python file in AppContainer probe

SovereignAI-Starter/scripts/appcontainer_user_code_smoke.py

@@ -0,0 +1,11 @@
+"""Harmless smoke payload used only to verify staged Python execution."""
+
+from pathlib import Path
+import sys
+
+result = Path(__file__).with_name("execution-result.txt")
+result.write_text(
+    "sandbox-python:" + ".".join(map(str, sys.version_info[:3])),
+    encoding="ascii",
+)
+print("sandbox-python-smoke-ok")