V.R391 — Capacity Equation as Qualitative Mechanism

The capacity equation provides correct qualitative behavior (K₀ → logarithmic potential → flat curves), interpolation function μ_τ(x) = x/√(1+x²), and regime classification. It does NOT provide the correct quantitative amplitude (v_lin ~ 0.07 km/s vs 150 km/s). The algebraic identity a₀ = c²/(2ℓ_τ) provides the amplitude.