nx_regbatch_gate.nx

nx_regbatch_gate.nx -- INDEPENDENT GATE: batched durability in reg_put. Correctness FIRST, speed second. INHERITS nx_gate_verdict (D001). A speedup that loses rows is not a speedup, so this gate proves the SAFETY properties before it looks at the clock: u2605VISIBILITY IS NOT DEFERRED. reg_put_deferred writes the segment and renames the manifest exactly as reg_put does -- only the power-loss barrier waits. A row must be readable IMMEDIATELY, before any sync. If that were false the batch would be a lie, so it is asserted first. u2605THE TWO PATHS MUST AGREE BYTE-FOR-BYTE. Same body, two entry points -- proven by writing the same record both ways and comparing what comes back. This is the anti-fork tooth: nx_gate_verdict once forked between trees and an identical migration bought different capability depending on where it ran. One body cannot fork; this check is what keeps it honest. u2605THE INDEX SURVIVES. A batched put must still land in the enumeration index, or a fast write that nothing can find is worse than a slow one. Only then: u2605the batch must actually be faster, or the whole change is unjustified complexity. license_tier: ORIGINAL No hw writes (Rule 26). expect_exit: 0