Design Blueprint: Error Budget for Chronometric Levelling Across a 1000 Kilometre Fibre Clock Network

Design blueprint derived from the source paper (DOI 10.5281/zenodo.24155005): A continental fibre network does not fail because its clocks are insufficient; it fails, if it does, in the accumulation of small link terms and in correlated environmental terms that do not average down with segment count. This study builds a segment-by-segment budget for a thousand-kilometre chain. The design question is concrete: with ten repeater segments, two endpoint clocks and a stated tide-model term, what height uncertainty survives, and which term should money be spent reducing first? The computed results, taken from the deposited script, are as follows in summary: The computed segme 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.