CDN-244 · The Frozen Sample — GCFT Dark-Sector Book Arc (Art Edition)

CDN-244 freezes the holdout cluster sample required by CDN-243 and locks the literature-provenance schema for every input the seven-term κ-proxy demands. Of the 16 candidates listed in CDN-243 §3, one is excluded (MACS J1206.2-0847 — CLASH overlap with the CDN-240 sample) and 15 are committed: Abell 1689, Abell 2204, Abell 2261, Abell 2390, MACS J1149.5+2223, RXC J2228.6+2036, Abell 2744, MACS J0717.5+3745, Abell 370, ZwCl 1358+62, Abell 851, Abell 1758, Abell 2163, MACS J0416.1-2403, and RX J1347.5-1145. For each frozen cluster the canonical source paper, table, and column is named in advance for the six required inputs (M₂₀₀, λ richness, m_off, s★/g, τ, μ relaxedness) and the two derived inputs (relaxedness flag and the formation-history proxy φ). Borderline-retained Abell 2261 has an auto-drop rule: if CDN-245 ingestion discovers inadvertent overlap with the CDN-240 sample, it is dropped, N falls to 14 (below the CDN-243 §3 minimum), and the inability-to-test branch fires before the proxy is run. The substantive artefact is cdn244_holdout_inputs.json, included in the bundle. All value fields are null by construction. CDN-245 will populate them from the named sources, log any substitution with a substitution_reason field, and record the canonical-JSON SHA-256 of the populated file (the empty-shell hash is supplied so any post-publication edit to the schema is detectable: 0ecfd1fdbd757aa2357d3cc05a82d70e590e2f74fbc3d8a2a27d9f0758a8f0f7). No parameter value is read in this paper. No proxy is evaluated. No proxy coefficient is modified. No "class hint" is promoted to a class assignment — those are starting guesses the proxy will overwrite in CDN-245. Art Edition with star-field design system (seed 244), built on art_base.py codifying the GCFT Art Edition Layout Reference. Lock: CDN244_FROZEN_SAMPLE_LOCKED.