Design Blueprint: A Quantum Key Distribution Terminal with Torsion-Phase Stabilisation

Design blueprint derived from the source paper (DOI 10.5281/zenodo.24138548): Quantum key distribution turns the disturbance of quantum states into an alarm: any eavesdropping on the quantum channel raises the error rate, and the secret key rate falls as errors rise. Status: DESIGN BLUEPRINT — SIMULATED, NOT MEASURED — NOT BUILT. All numbers are simulated values from the source paper's computation, deposited with this blueprint as compute.py and results.json. AI-use disclosure: Dave, an AI research system, assisted with the computation and drafting under the author's direction; author of record William Alexander Aldred.