nx_plane_check.nx

nx_plane_check.nx -- VERIFY the TSV<->NXR1 bridge against REAL production plane data, READ-ONLY. WHY THIS EXISTS AND WHY IT COMES BEFORE ANY WRITE: seq1369 shipped the bridge with a gate built on SYNTHETIC fixtures. Fixtures prove the code does what I thought; they cannot prove real rows survive it. Before a single production plane is rewritten, every row of that plane must be shown to make the round trip tsv -> NXR1 -> tsv BYTE-IDENTICAL. This organ does exactly that and WRITES NOTHING. FAIL-CLOSED, and specifically against the VACUOUS-VERIFY TRAP: an empty or unreadable plane exits 4 rather than reporting "0 mismatches, all good". Zero rows checked is not a pass. This is the same trap the TSV-retirement law already warns about (rowset-identical AND NON-EMPTY). COVERAGE IS REPORTED, NOT ASSUMED: it loads via sts_load_honest, whose flags expose that the q:n count key can be LOWER than the rows actually present (measured on debt-: q:n said 125 while 629 segments held 734+ rows). If rows exist beyond the declared count, this exits 5 -- the rows it checked were fine, but the plane was not fully SEEN, and a partial check must never be presented as a complete one. EXIT: 0 all rows byte-identical and plane fully seen · 2 usage · 3 mismatch · 4 empty/unreadable 5 clean so far but coverage incomplete (rows beyond the declared count) license_tier: ORIGINAL No hw writes (Rule 26).