Configured Observation Planes: Planck Scale, E = mc², and the Einstein Field Equations from Probability Simplex Geometry

No existing framework in theoretical physics derives the gravitational coupling from pure geometry without empirical input. The Configured Observation Planes (COP) framework does: the fixed-point condition d* = 1/d* forces G = 1 in COP natural units, with no free parameters and no experimental measurement required. This is the central result. The COP framework derives wave equations, curvature, holonomy, and selection dynamics from a single Markov model on the probability simplex, without assuming prior spacetime. From that foundation, this paper establishes four results. First, the derivation of Newton's constant: the GU-Closure fixed-point condition forces the admissibility stiffness κ to 1, identifying the gravitational coupling and KG mass parameter as the same geometric object with value G = 1 in Planck units. Second, at the fixed points d* = ±1 with vanishing momentum, the COP dispersion relation yields E = ±mc²; the two signs are the two sheets of the Z₂ cover of the exceptional divisor E₁ ≅ RP¹, giving particle and antiparticle from topology alone. Third, COP provides all three Jacobson ingredients for deriving the Einstein field equations G_μν = 8πG T_μν: the entropy floor H_min(ε) from Corollary 30, the COP temperature forced by seam geometry, and the Seam Consistency Condition of GU-Closure as the universality condition. The stress-energy tensor T_μν is proved from COP via the Noether theorem. Fourth, Spencer (2026e) derives the Price equation, Darwin kernel (the Markov operator of natural selection), and Nash equilibria from the same Markov structure: selection dynamics is a third specialization of the COP geometry alongside QM and GR. Quantum mechanics, general relativity, and Darwinian selection are three coordinate descriptions of one fixed-point geometry on the probability simplex. Two metric normalization computations complete the standalone EFE proof and are identified as primary obligations of subsequent work.