Exact GEP Fusion Selector Derived, Dynamical Orientation Not Yet Selected

Stone 2C addresses the next bounded question in the Granular Entropic Physics (GEP) chiral program. Stone 2A established that faithful quaternionic Q8 holonomy is compatible with an irreducible gapped Chern pump, while Stone 2B derived the corresponding four-state carrier and its complete internal matrix algebra from the local three-spinor sector of GEP. The present paper asks whether the canonical composition law of local GEP maps can distinguish this carrier, transmit its Pauli multiplicity, and select a dynamical orientation. The exact local map algebra is A6=End2T(V⊗3)≅M2(C)⊕C⊕C. Equipping A6 with the Hilbert–Schmidt geometry inherited from its action on V⊗3, let μ:A6⊗A6→A6 denote blockwise multiplication. Its positive normalization operator D=μμ† has the exact spectrum spec(D)={1×4,(21)×2}. For the central idempotent Q↔(0,1,1), complementary to the M2(C) block, −logD=(ln2)LQ=L(ln2)Q. Thus the normalization-cost generator is represented by a unique canonical positive algebra element. On the local spinor space, the corresponding element λQ has spectrum specV⊗3(λQ)={0×4,λ×4}, and its kernel is exactly the Stone-2 carrier P0V⊗3≅W⊗M,dimW=dimM=2. The normalized coisometry μˉ=D−1/2μ produces a compatibility projector Π=μˉ†μˉ. On M2(C)⊗M2(C), this projector is exactly a rank-four Bell-type identity wire, ΠM2=IL1⊗∣Φ+⟩⟨Φ+∣R1L2⊗IR2,∣Φ+⟩=2∣11⟩+∣22⟩, which transports the complete Pauli multiplicity algebra across a compatibility bond. A mandatory negative result is equally exact. Fusion is equivariant under the full adjoint U(2) action and therefore treats the two channel orientations R and R−1 identically: FAIL_ORIENTATION_SELECTION_FROM_FUSION_ALONE. The established result is an exact finite-dimensional selector-and-transport theorem. Its interpretation is that canonical GEP fusion distinguishes the Stone-2 carrier block and supplies a lossless algebraic compatibility wire. It does not yet derive a physical Hamiltonian, spatial gluing rule, collective orientation coupling, QWZ dynamics, Kaplan wall, Weyl boundary mode, or Standard-Model anomaly structure. A collective orientation interaction remains a clearly identified candidate for the next microscopic test.