nx_map_file_gate.nx

nx_map_file_gate.nx -- gates the DEBT-EATEN file I/O floor (2026-07-15): (a) sys_read_file now sizes its buffer from the file itself (the old fixed 4 GiB cap SILENTLY TRUNCATED bigger files into plausible-garbage tensor reads); (b) NEW sys_map_file = read-only file-backed mmap (any size, zero-copy, only touched pages resident -- the lazy-MoE serving shape). Teeth: T1 sys_map_file: exact length + BYTE-IDENTICAL to sys_read_file on a patterned temp file T2 honesty: absent path -> 0 pointer + 0 length (both functions) T3 read-only by construction: the mapping's first byte reads correctly twice (stability), and the pattern check covers head/middle/tail (page boundaries crossed) expect_exit: 0 license_tier: ORIGINAL No hw writes (Rule 26).