_race6_claude.nx

_race6_claude.nx -- the CLAUDE lane for autonomy race 6 (handwritten single-pass PNG chunk census; the yardstick). Lane contract: read /tmp/race_input.bin, print NCHK= IHDR= IDAT= IEND= W= as key=int lines. PNG: 8-byte magic, then chunks [len u32 BE][type 4cc][body][CRC 4B]. NCHK = well-formed chunk count, -1 refused (bad magic / truncation / overlong); finds = body offset RELATIVE to the chunk area (byte 8), -2 refused/absent; W= = u32 BE at abs byte 16 (IHDR width) whenever the magic is intact, -2 otherwise. license_tier: ORIGINAL