nx_logtail_gate.nx

nx_logtail_gate.nx -- TEETH FOR THE SHARED HONEST TAIL READER (nx_logtail.nx, debt 1786054115). Inherits nx_gate_verdict (gv_ctr/gv_head/gv_check/gv_verdict) rather than rolling its own counter, per the D001 MIGRATE-ON-TOUCH law -- a new gate that hand-rolls a verdict is a new D001 row. THE LOAD-BEARING TOOTH IS T4, THE NEG-CONTROL. Asserting only "the newest record survived" would ALSO pass for a reader that quietly returned the entire file, so it cannot discriminate a tail read from no read at all. T4 demands the OLDEST record be ABSENT, which is the only assertion that distinguishes "kept the tail" from "kept everything" -- and keeping the wrong end silently is the entire defect class this lib exists to close. license_tier: ORIGINAL No hw writes (Rule 26). expect_exit: 0