Varying-Coefficient Mixture-of-Experts Models // Fits Gaussian, Binomial, and Negative-Binomial varying-coefficient mixture-of- experts models with local-linear estimation, explicit label alignment, bandwidth selection, diagnostics, bootstrap inference, analytic-style confidence bands, coefficient- specific analytic generalized likelihood-ratio test (GLRT) diagnostics with optional bootstrap calibration, and local-grid or joint-path expectation-maximization fitting engines.