c2e5c94cd7
Workspace moves stamp agent.session_cwd so a lazily started Codex thread starts in the moved-to directory. Agents that never had the attribute (test doubles, slotted objects) must keep working, so stamp only when the attribute exists. Test stubs of _set_session_context mirror the new cwd kwarg, and the Codex gateway test asserts the contract (no pinned session cwd) instead of the attribute's absence.