v1_neg: uid=0 (v1 twin-fact riders)
STEP sockets ready
PASS R1 echo reflects to arrival hook only (1 byte back from 'e1')
PASS R1 cross-wired hook stays silent (ring inert)
PASS R2 echo bounces control msg back as NGF_RESP (no relay)
PASS R3 hole eats data (nothing returned)
PASS R4a v1 hole rejects GET_STATS with EINVAL (no rcvmsg -> framework default)
PASS R4a no reply shipped back
PASS R4b under-sent GET_STATS (arglen=32, 0 bytes sent) -> EINVAL, twin of DF-3558 ABSENT
PASS R4b no reply shipped (no OOB oracle)
RESULT riders pass=8 fail=0
V1RC=0