integrable-boundary-certificates v1.2.6: exact-arithmetic engines, machine certificates and verification kits

Exact-arithmetic engines, machine certificates and verification kits for the papers "Commuting integrals of motion for free bosonic CFTs revisited" and "Opers for the cylindrical integrals of motion" (E. Vitchev, 2026), as release v1.2.6 of https://github.com/evitchev/integrable-boundary-certificates. The directory opers-2026-10 is the verification kit of the opers paper: 235 checks, each paired with a tamper drill that must fail, re-run the archived computations behind the paper's claims and compare them with the archived outputs exactly. Release v1.2.6 adds 58 checks: the spectral theorem for positive integer a (Solution 3 at t = (3a+2)/(a+2) and Solution 1 at t = 2a+1, with a closed-form constant), and the comparison of Solution 1 with the U(1) coset of N = 2 superconformal symmetry. The new directory super-kdv-2026-10 computes the cylinder vacuum eigenvalues of the N = 1 super-KdV integrals of motion I_1 to I_9 in the Neveu-Schwarz and Ramond sectors, exactly and symbolically in the momentum and the background charge. Pure Python; the dependencies are sympy and mpmath (the Lean certificates additionally need Lean 4.24 with Mathlib). The run records are in opers-2026-10/logs (VERSIONS.txt and v126_*) and super-kdv-2026-10/logs: full run and all drills under Python 3.8.10 / sympy 1.13.3, and the new checks also under Python 3.12.8 / sympy 1.14.0. RELEASE_MANIFEST.json pins the SHA-256 of every file, and code/public_lint.py re-verifies them. License: MIT, except wolfram/OPEdefs/ (K. Thielemans' OPEdefs, redistributed unmodified under the terms in its own header).