nx_heartbeat_monitor_gate.nx

nx_heartbeat_monitor_gate.nx -- the REFEREE for WMS-M1 (liveness / heartbeat monitor). Proves the nx_heartbeat_monitor detector (a) FLAGS exactly the crashed stream as STALLED, (b) NEGATIVE CONTROL: the two freshly-beating streams are NOT flagged -- a detector that returns STALLED for everything FAILS this lane; one that returns ALIVE for everything FAILS the core lane -- so the same scan call cross-checks both, (c) TAMPER: the stalled stream RESUMES beating (a fresh max-epoch beat) -> STALLED CLEARS -- proves the monitor tracks the LATEST beat, not a sticky first reading, (d) malformed line surfaced (count > 0, ws_ledger no-silent-skip discipline). No-false-green: GREEN requires ALL lanes. TIME IS INJECTED (NOW / THRESHOLD are gate constants; every beat is placed at a controlled epoch via hb_beat_at) -- the gate does NOT depend on real elapsed wall-clock, so it is deterministic and re-runnable. WRITE DISCIPLINE (the torn-line bug): the gate's OWN evidence record is assembled into ONE buffer and emitted with a SINGLE locked fa_appendz -- to a UNIQUE scratch path (epoch+pid) so concurrent gate runs never collide (eat our own dogfood). The row-by-row lines go to fd 1 (the terminal -- uncontended, same exemption the ws_ledger gate uses for stdout). Exit 0 GREEN, 1 RED. Sovereign: only nx_syscalls + nx_heartbeat_monitor. license_tier: ORIGINAL