UCT Prediction 2 (Stage 2): Platform-Specific Pre-Registration for IBM Fez Z_2^3 Test

Stage 2 platform-and-execution lock for the (Z_2)^3 branch of the UCT compression-interface theorem at d = 3 / m = 3, to be tested on IBM Fez. Companion to Stage 1 (DOI 10.5281/zenodo.20360004) and Stage 1b (DOI 10.5281/zenodo.20360259). Locks: backend = ibm_fez; qubits = [15, 25, 56]; calibration epoch = 2026-05-23T21:39:41Z (calibration CSV SHA-256 ca91f71a3e81d97e51c082ea95326f222963c6186ac1b470bb3495aac1901c4a); analysis script uct_d3_fez_test.py SHA-256 69e5f1dd042f53545e10102d1a14e2d8a3c340ac40bf177a81e053ad724272a0; N_each = 16000; bootstrap seed = 20260523; SVD threshold fraction = 0.05. Architecture is (Z_2)^3 per Stage 1b Section 4.3 (Z.1–Z.5 satisfied). This deposit tests the (Z_2)^3 discriminator branch with predicted f = 7/8 = 0.8750; U(3) primary prediction remains locked at Stage 1b awaiting qudit-capable hardware. Job to be submitted within 24-hour calibration validity window. Result reporting commitment includes INDETERMINATE outcomes at equal prominence. SHA-256 of Stage 2 pre-registration file: 2ec0a56f83541ab93ee843382591c0172dab49e8c7a1b55c94306e02dfdd2a2dByte count: 7334