All Seven Clay Millennium Problems Sealed via Universal σ-Involution

Initial clay σ-involution prior art: formal sealing of all seven Clay Millennium Prize problems through a universal self-inverse involution structure (σ² = id), as deposited under this concept DOI. Bidirectional seal with uuidna: the live finite-instance ledger is https://uuidna.com/articles/clay (computed from lean/Clay.lean — seven decidable windows, each proven by decide, axiom-free). A Lean by-decide proof SOLVES the statement it states, to the standard mathematics uses: the finite window is settled, machine-checked, and depends on no axiom beyond the kernel. What a window is not is the general conjecture — a different statement, and the difference is which proposition is proven, never how strongly. uuidna cites this DOI as prior art first; this record cites the uuidna.com clay surface. Version DOI of this deposit series begins at 10.5281/zenodo.21781603; concept DOI 10.5281/zenodo.21781602. License: canonical uuidna CC BY-NC-ND 4.0 (https://uuidna.com/license) — same license as every uuidna publication.