nx_vsretract.nx

nx_vsretract.nx -- withdraw a comparative claim that turned out to be wrong. argv: <domain> <scope> <reason> Appends a VSRETRACT line to the same ledger nx_vsbest writes. nx_vsroll_lib walks that ledger in order, so a retraction clears the (domain, scope) back to UNMEASURED, and a later nx_vsbest claim after a clean re-run legitimately re-establishes it. WHY THIS EXISTS: I admitted search|latency=behind on a benchmark that had starved our own engine (the harness held a 892MB FTS5 index it had just spent 483s building, and I timed our search under that contention). Re-timed clean, our search answers in 1-6ms. The claim was wrong and there was NO WAY TO WITHDRAW IT -- nx_vsbest only appends. Five routes to a fabricated WIN were closed by construction; there was no route to correct an honest MISTAKE. ★★★★★AN AXIS THAT CANNOT BE UN-CLAIMED CAN BE POISONED BY EXACTLY ONE BAD MEASUREMENT. RULE 13: this DELETES NOTHING. The original claim stays in the log as history -- the retraction is a later row that supersedes it. A reader can still see what was claimed, when, and why it was withdrawn, which is the whole point of an append-only ledger. A REASON IS MANDATORY. A retraction with no stated cause is indistinguishable from someone quietly deleting an inconvenient loss, and this axis exists to make that impossible. license_tier: ORIGINAL No hw writes (Rule 26).