Contextual Born-Weight Uniqueness under Stabilized Orbital Invariance, with a Protected Readout Model

We study a conditional uniqueness problem for event weights in finite quantum contexts and a protected physical model in which its orbital premise can be made explicit. A finite contextual game consists of a normalized state and a finite PVM, with event size x(E) = ∥PEψ∥². We define stabilized orbital equivalence of binary terminal states by isometries on nonconsequence factors while fixing a binary consequence register. For orthogonal binary terminals the stabilized orbit is completelyclassified by the two branch norms. It follows that any positive, normalized, finitely additive event valuation that is invariant on these orbits and is defined on a ternarily rich class must equal x(E). The five assumptions are logically independent. We then distinguish geometric orbital equivalence, physical inaccessibility, and the separate normative premise of equal value. Uniform physical sealing is characterized by factorization through the conditional expectation onto an accessible algebra, with dimension-free diamond-norm stability bounds. Finally, a four-qubit collective-noise sector supplies a noiseless logical qutrit realizing ternary richness and an ideal binary readout at the selected grain. Under explicit post-readout sealing and interface-closure assumptions, same-size acts have the same admissible future consequence statistics. In a restricted instantaneous- protection model, total 2-local Hamiltonians cannot perform an informative protected readout, whereas an exact 3-local construction exists. The physical results do not derive event additivity or orbital value indifference; those remain explicit representation and normative premises.