Context to Outcome: Variational Bundle Reduction on a Non-Invertible Basis

This Brick closes Born O2 by replacing the “outcome maps from structure-group reductions” postulate with an explicit context-to-reduction construction. It constructs a canonical context functional on the observational macrostate space, proves existence and almost-everywhere uniqueness of its minimizer on the context homogeneous space, and then upgrades the minimizer to a structure-group reduction and a descended order parameter. It exports the resulting interface needed by Lemma 8 and Proposition 1 of the Spin/Phase/Holonomy brick to produce quotient-compatible outcome maps without importing Hilbert projectors. It leaves one explicit calibration obligation, namely the derivation of the overall coupling scale that controls dynamical sharpness but not the induced partition.