nx_fsops_write_gate.nx

nx_fsops_write_gate.nx -- END-TO-END gate for the estate's WRITE PATH (the binary behind the nx_fs_write tool). Until 2026-09-05 this organ -- every seat's edit, append and write -- had NO gate at all. This one forks the SUBJECT ARTIFACT on a fixture tree under /tmp/<gate>/ and proves the idempotency-key contract added the same day (/compare/dataio DI4): a keyed write applied once is returned, not re-applied, on a retry carrying the same key; a different key or no key keeps today's behaviour exactly (a neg-control each), and a REFUSAL never poisons a key. The subject is forked IN PLACE by an absolute path (NAS /tmp is noexec); only its CWD is inside the fixture, which is where its CWD-relative ledger knowledge/status/fswrite_idem.jrnl lands. exit: 0 GREEN / 1 RED (gv_verdict law).