§6.2: add offset_of! asserts to SharedHeader/AddReply/control structs so a same-size field reorder is a compile error, not silent corruption (size+Pod alone miss it).
§6.1: add XusbShm (64B) + PadShm (256B, incl device_type@140) layouts + Global\ name helpers + magics to the proto crate as the single source of truth, with offset asserts pinned to the shipped wire layout — kills the hand-duplicated literal-140 host/driver drift hazard. Enables bytemuck min_const_generics for the >32-byte reserved tails. Host + driver consumers switch in a follow-up.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
enricobuehler
95dcef3515