The Junction Identity as Organizing Principle of the IKBL Series: On the Geometric Significance of χ · β_int = π

This technical note demonstrates that the Junction Identity Φ = χ · β_int = π is not a numerical coincidence but the algebraic signature of a closed non-orientable geometry. The two invariants χ = 40/7 and β_int = 7π/40 were derived independently from different physical requirements in separate documents; their product is exactly π because the C₇ cyclic symmetry enforces its own cancellation. We show that every downstream result in the IKBL series — the cosmological dipole, the arrow of time, the dark sector projections, wave-function collapse, entanglement, the fine-structure constant, and the dark energy equation of state — is a different expression of this single closure. The framework has a single falsification point: a tomographic birefringence measurement of β_int accessible to SKA and Rubin/LSST either reproduces Φ = π or falsifies every result simultaneously.