nx_ts_slot_router_gate.nx

nx_ts_slot_router_gate.nx -- TS3: A FLIP THE CLIENT CANNOT SEE, AND A COLD SLOT IT REFUSES. /compare/trafficsafety rung TS3, accept rule taken VERBATIM from trafficsafety.plan and not re-invented here: "a flip changes which slot answers with zero failed requests across the flip, a slot that fails its warm-up probe is NEVER flipped to, and the front door's own uptime is unbroken across the whole exercise." ALL THREE CONJUNCTS ARE TESTED SEPARATELY AND EACH NAMES ITSELF, because a compound assertion that will not name its failing conjunct is a false-alarm generator -- the reader always guesses the alarming third. THE SUBJECT IS THE REAL ROUTER BINARY, fork+exec'd, not a function called in-process. And the gate plays OWNER of the front listener, handing it over with ts_handoff_publish, which does double duty: it is a deterministic readiness edge (the publish returns only once the router asked for the socket) AND it demonstrates the property TS3's own risk row demands -- that the one component which must never restart is itself replaceable without a gap, which is why TS3 depends on TS1. THE COLD-SLOT CONTROL IS A REAL DEATH, NOT A FICTION. Slot A's server is killed AND its listening socket closed, so the port genuinely refuses connections; only then is a flip back to A attempted. A guard that gates a destructive action must be wrong in the direction of doing nothing, and moving live traffic onto a dead slot is the destructive action here -- so the control asserts three things, not one: that the flip was REFUSED BY NAME, that the active slot did not move, and that the client still reaches the healthy slot afterwards. A refusal that quietly parked traffic nowhere would pass the first and fail the third. SAFETY: loopback only; every port is FOUND by a bind that would have failed had it been occupied. Nothing live is touched -- this router is standalone by design and fronts only the gate's own two throwaway slot servers. Fixtures live under /tmp/<gate>/ and setup clears them, so a run cannot inherit a previous run's state file and report on it. expect_exit: 0 license_tier: ORIGINAL No hw writes (Rule 26).