Melody as Conservation Under Constraint: Independent Derivation of Sub-Limit Dynamics from the Domain of Melodic Invariance

We derive the four structural properties of sub-limit dynamics, finite vocabulary, early saturation, interaction bottleneck, and efficiency paradox — from the melodic domain. Starting from the observation that a melody maintains its identity under systematic transformations, we identify the melodic pixel as the ordered pair of consecutive intervals (r₁, r₂): the first local configuration in which curvature of the melodic profile becomes defined and classifiable under a finite constraint L. This is the first explicit second-order pixel in the SDL framework. The consumption type is T3 (trajectory-consumptive), the regime R2 (branched attractor). Melody is classified as Q-family E (conservation through exchange, Q21), structurally distinct from harmony M1 (Q-family F, Q20). This establishes music as the first verified acoustic case of substrate bifurcation: one continuous acoustic space generating two structurally independent CGS readings under the same physical limit. Eighteenth verified domain.