The Proto-Spinor: Conditional Spinorial Closure and the q79 Interface

We isolate the part of the proto-spinor construction that is mathematically forced after its geometric premises are stated. A world-in-world field compares two oriented rank-three bundles; its nine local components do not multiply manifold dimensions. If closure data must retain the nontrivial loop class in the three-dimensional rotation group, the faithful continuous double-cover carrier is spinorial and is represented by the corresponding two-dimensional unitary group. This is a conditional lifting theorem, not a derivation of internal dimension three or of physical fermions from admissibility alone. For the selected q79 degree-three spectral cover we record the exact trace split of ranks 1+2, the common 1+2+3 carrier, and the local binary-dihedral lift of signed sheet monodromy. The shared circle is a specified pullback of one universal flat cyclic differential line of order 64, not merely an isomorphic fiber. Its determinant, CLN, root-plane, and finite-Hessian actions intertwine exactly. The BHT and Hori fiber transforms share one orthogonal complex structure, and the binary sheet group has exactly two conjugate phase-root lifts. Strict global Spin closure remains equivalent to a branch-relator obstruction calculation; the closed result is SpinC and finite symbolic. Circle, lens, and nil remain typed phase, finite-transport, and anchoring roles. Lorentzian spinors, masses, and particle assignments remain downstream realization problems.