P74: rho_c as the Natural QCD Density — Numerical Observation and Open Conjecture: rho_c = Lambda_QCD³/ℏ³c³

The CCEGA framework contains one phenomenological parameter: ρ_c = 7.4 ρ_nuc, fixed to reproduce M_max = 4.56 M☉. We report the numerical observation that ρ_c = Λ_QCD³/ℏ³c³ with Λ_QCD = 208.7 MeV — within experimental uncertainty (210 ± 14 MeV). This is the unique density constructible from Λ_QCD and fundamental constants alone. If this relation has a dynamical origin in the brane geometry + QCD, CCEGA would have no free parameters. We document three supporting observations, identify the open problem, and propose a falsification path. The derivation of ρ_c from first principles remains the deepest open problem of the framework.