Assumption: Degenerate physical code and leakage audit

The internal states $|0{⟩}_A,|1{⟩}_A$ have equal energy, charge, and declared angular-momentum labels. The common center-of-mass wavepacket, injection trajectory, and arrival-time distribution do not depend on $x$. On the code, the specified smeared macroscopic source operators act as scalar multiples of the identity.

All other accessible preparation, prompt-scattering, capture, and exterior-probe records are included in the declared output channel, or excluded by an explicit access boundary whose leakage is separately bounded.