Adds an optional member-level launch_wrapper for local built-in Pi and Codex seats: an argv prefix applied at native launch and carried through restore, handover, restart and runtime switch (migration 150 stores it). For Pi the wrapper wraps the child process the runner spawns, inside the unwrapped runner; flat specs carry the field. Once selected, a wrapper is never silently skipped. rig-spec.md says retention applies to existing seats, not newly imported nodes. Native cells cover the wrapped paths with an rc PATH export, a readiness marker and wrapper execution markers. Sandbox, memory and tooling remain the operator's choice. Reported by smota in D#2328.