Epigenetic Alterations Module

This is a mechanism module, not a specific disease. Disorder entries reference individual nodes via conforms_to (e.g., "epigenetic_alterations#Altered Epigenetic Regulation of Gene Expression"). Conforming nodes in disorder files should include the corresponding biological processes and causal edges, specialized to their disease context. The module captures the conserved epigenetic-drift chain and its biomarker (epigenetic-clock) and reversibility angles, but deliberately does NOT embed specific clock coefficients or contested reprogramming-rejuvenation claims; those belong on the relevant disorder or method entry. Worked conformers: Hutchinson-Gilford Progeria Syndrome (heterochromatin loss, attaching at the "Age-Associated Epigenetic Drift" node), plus the chromatin/DNA-methylation-machinery Mendelian disorder that attaches at the central node - Heyn-Sproul-Jackson syndrome (DNMT3A gain-of-function hypermethylation recapitulating age-related DNAme gains). Scope boundary against the germline chromatinopathies. Wiedemann-Steiner syndrome (KMT2A) and Bainbridge-Ropers syndrome (ASXL3/PR-DUB) previously conformed here for want of a better target. They now conform to `epigenetic_machinery_neurodevelopmental_dysregulation` instead, which models the Mendelian disorders of the epigenetic machinery. The distinction is the explanandum: this module is about age-associated, partly stochastic drift of a normally-established epigenome, whereas those disorders begin with a germline lesion in a machinery component and disrupt neurodevelopment from the outset. A germline chromatinopathy should conform there, not here. Heyn-Sproul-Jackson is retained because its DNMT3A gain-of-function hypermethylation is curated specifically as recapitulating age-related methylation gains - the drift phenotype this module models - rather than only as a machinery lesion. Note the GO "DNA methylation" term is obsolete, so methylation drift is bound via "epigenetic regulation of gene expression" and "chromatin organization" and described in prose. Key conformance target: "epigenetic_alterations#Altered Epigenetic Regulation of Gene Expression".