Multi-Layer Decomposition of Functional Community Restructuring // Implements the 'ASC-CFD' (Assemblage Shift Characterization - Community Functional Dynamics) framework for decomposing functional community restructuring into positional (centroid displacement), dispersive (functional dispersion), and boundary (convex hull volume) components. Provides hierarchical null models (structural, quantitative, identity) to evaluate statistical significance and species-level leverage analysis to identify taxa driving functional shifts. Supports both temporal (paired) and spatial (pairwise) comparisons.