nx_coindex_gate.nx

nx_coindex_gate.nx -- liar-killed GATE for the conflict-free co-edited index (R-ORCH-2). Proves the append-and-derive property that KILLS the parallel-session merge-dance: many appends (the concurrent-writer stand-in -- concurrency safety itself is inherited from the flock floor, WMS R11 MEASURED 0/144-lost-vs-git-132) all land with NO loss; the reducer keeps LAST-write-wins per slug (a session re-banking its entry supersedes its own prior, never another's); a fresh slug is added, never colliding. Load-bearing neg-control: the superseded line MUST be absent from the derived index (proves last-wins actually drops the stale entry, not just appends). Exit 0 on 6/6. license_tier: ORIGINAL expect_exit: 0