Work package D: input, preparation, and readout errors

Required data. Common representations, admissible input changes, plateau restrictions, preparation control, and a detector model in a compatible metric.

Completed here. Theorem thm:readout proves an end-to-end scalar budget. Proposition prop:noise constructs the additive-noise POVM and states the exact cross term. Proposition prop:instrument supplies sequential probabilities for specified instruments.

Remaining target. Instantiate the classical metric and switch bounds from complete source definitions. Construct any proposed physical detector. Replace a probability-only carrier allowance by a moment-compatible law comparison when RMS claims are made.

Completion criterion. Every term controls the same stated quantity and carries the correct units. Outside-plateau errors and nonzero noise cross terms are retained.