# Port movement scratch initialization and callback plans

RE-985. Focused validation: `cargo xtask test-group rust-client-move-scratch`. [Machine report](rust-client-move-scratch.json).

Rust owns an exact268-byte scratch slice and returns ordered zero/mode-callback plans. Twelve source/Rust fixtures compare every scratch word, guards and callback order. Invalid client slots reject before mutation; slice ownership prevents overwriting neighboring frame words. Callback execution and feedback are deliberately left to a future native adapter.