GATE D27
Orbit-compressed unlabeled CRT: BLOCKED
What changed
D26 proved the direct coordinate CRT threshold but measured the labeling obligation as a net-negative cost. D27 keeps the lower reconstruction threshold while removing the permanent per-prime labels, holding the global state as an unordered multiset of CRT root classes together with its stabilizer. Merging a new prime is done by enumerating matching orbits, that is transport matrices over the compatibility graph, rather than raw permutations. The orbit quotient is proved exact, with no false merge and no false split, and the sign-lift factor of 2^13 per prime is itemized for the first time. The decisive result is a certified obstruction, not a worst-case proxy: a single generic distinct-residue merge already produces 25,505,877,196,800 orbit children, about 2^44.5, which exceeds the frozen 2^42 state ceiling at merge depth one. The gate closes the forward orbit-enumerative unlabeled root-CRT architecture under the frozen caps. It does not rule out bidirectional or hybrid methods, and it does not decide the conjecture. LRC(13) remains open.
Evidence
Verification: double · I2 · 8 artifacts (reports, verifiers, corruption suites, manifest with SHA-256)