Research compensated P104 null-pair shear

[1337isnot1337]

This adds an exact, source-pinned screen of a ten-term compensated null-pair shear on PR717’s P104 decoder. Across all 1,839,360 pivot/vector-pair cases in the declared two-coordinate Gaussian-unit domain, the replacement block costs at least 21 copied-rank units instead of 7; the complete decoder costs at least 70 instead of 56. The exact P104 relaxation still clears the inherited five-percent screen, but that headroom comes from the unchanged P104 port/centre profile and the null-pair adds cost. No supplier, selected κ, or theorem change is claimed.

Reproduce with python3.12 -I -B research/p104-nullpair-compensated-shear-seed318bd5/verify.py. The registered package replay passed locally. It checks both 104×104 identities, the exact F2 support-rank histogram, six rank-one setup/cleanup charges, the wrong-sign control, and exact source pins.

Scope: seed 318bd5e5f93c401334e29c6764720302, base 0b1cccf86e2f5132ed286a26ef0a681a495740ea, selected-record SHA-256 10b9e340fd8e354a37a0c4813c90e5de1dd42044b5f6aca4a3fc5a42b685fa32. This changes the term count with an isotropic null pair, unlike the open P104 one/two-shear screen; it complements the all-m residual-rank theorem with one concrete copy-cost search. Prepared with substantial OpenAI Codex assistance; no independent human review is claimed.

[Mister-Meeseeks]

Batch review at 646eb3db23f564d3b9aefc6ded877d1a17646fc4.

Merged to main, preserving the original contributor commits and package attribution.

Reviewed scope: Complete1839360 ordered distinct two-coordinate Gaussian-unit null-pair shears over eight P104 pivots have replacement COPY rank at least21 versus7. Exact decoder and representative transformed identity checked. This excludes only the stated one-pivot alphabet; favorable inherited P104 headroom does not constitute a new gain.

The pinned scoped command passed; the batch ledger contains its command, input hashes, environment and log. This incorporates the research/tooling contribution and does not change the selected κ or discharge the inherited multiplication-theorem assumptions.

Batch review, attribution and evidence. Thank you for the contribution.