Proto-Spinor Closure and Worldsheet Encoding in Modal Triplet Theory: A Conditional Local Bridge

Corrected fourth edition. This paper formulates the proto-spinor/worldsheet relation as a typed local bridge rather than a derivation of string theory. Near an aligned q79-compatible background, a bridge map sends proto-spinor and closure-strain perturbations to worldsheet coupling perturbations. Under an explicit quadratic-form intertwining condition and a controlled nonlinear remainder, the two descriptions share the same quadratic admissibility test on the selected subspace. Scope boundary. Worldsheet Weyl invariance, modular consistency, anomaly cancellation, ghosts, target-space equations, and the same-source connection intertwiner remain independent gates. Circle, lens, and nil are typed roles rather than literal product factors.