Add bounded stdin to owner execution

Assistant: codex
Assistant-Model: gpt-5.6-sol
Assistant-Session: 01a06def-6490-7033-8448-2eab2d12ed44

src/sandboxer/extensions/base.py

@@ -60,6 +60,7 @@ class SandboxExtension(ABC):
         execution_context: dict[str, str],
         timeout_seconds: int,
         max_output_bytes: int,
+        stdin_text: str | None = None,
     ) -> dict[str, object]:
         """Run a bounded command through an owner-mediated sandbox boundary."""
         raise NotImplementedError(f"{type(self).__name__} does not support execution")