Dissipative dynamics across physical systems exhibit organizing structural boundaries. The dimensionless damping ratio \(\chi \equiv \gamma /(2\omega )\) defines a stability architecture in which the critical threshold \(\chi =1\) marks a second-order non-Hermitian Exceptional Point (EP2). Within spatially flat \(\Lambda\)CDM, an exact algebraic identity is demonstrated linking the onset of cosmic acceleration to critical damping of structure growth: \(\chi _\delta = 1 \Longleftrightarrow q = 0\). This identity is a structural reformulation of the standard Friedmann and growth equations, not a new physical law; its scientific value lies in recasting a known kinematic transition as a stability-phase transition and in generating the falsifiable prediction that departures from flat \(\Lambda\)CDM produce a measurable, nonzero offset between the \(q=0\) and \(\chi _\delta =1\) transitions (identically zero under flat \(\Lambda\)CDM, generically nonzero in extensions). A substrate inheritance relation is then proposed as a leading-order projection approximation, whereby emergent modes acquire effective parameters from substrate precursors. Within this framework, the observed particle distribution is consistent with stability organization: long-lived matter occupies localized stability basins at \(\chi \ll 1\), while short-lived resonances occupy a secondary \(\chi \sim 0.1\)–1 band whose sub-cluster evidence is suggestive rather than conclusive. The framework is presented as a structurally grounded classification with defined scope and testable consequences.
