Why Quantum Probability is |ψ|² Proposed insertion: arxe_phenomena_v2.md, as addendum to phenomenon #15 Mode: B — structural derivation Builds on: Measurement problem document, Section 8.4 (Indecidability as Geometry) Date: March 2026 The question The Born rule states that the probability of a measurement outcome is proportional to |ψ|² — the squared modulus of the quantum amplitude. It is the most…