P26: Singularity: Why and How Physical Substrate Dynamics Make Infinite Density Impossible

General Relativity (GR) successfully models gravitational curvature and geodesic motion but permits singularities because curvature is treated geometrically without a physically compressible carrier medium possessing persistence, redistribution, entrainment, saturation, and coherence dynamics. This paper proposes that when gravitational deformation is treated as physically real and dynamically propagated through the Spaticle field 4 substrate, five stabilising mechanisms emerge naturally: outward rotational entrainment redistribution, finite propagation effects, nested-domain reinforce 6ment, vortex-core stabilisation, substrate restoring pressure, and coherence-threshold saturation. Together these mechanisms prevent unlimited local density divergence and replace singular collapse with finite organised compression structures whose maximum density ρₘaxfinite is bounded by the same substrate parameters that govern galaxy rotation curves and gravitational-wave carrier dynamics. The paper derives the maximum compression density bound from the full extended free-energy functional of the Spaticle field 4, where all stabilising terms originate from one substrate density ρₛ = 5. 9 × 10⁻²⁷ kg/m³ and the proton charge radius rₚ with no additional free parameters. The Rotational Sustenance Principle is introduced: no vortical compression core of any origin can persist without a continuous supply of surrounding rotating mass. A quantitative seed dissipation timescale τdissip = Rd/c is derived - approximately 59 minutes for a 10 M☉ isolated seed core - establishing that Pathway 2 (stellar collapse) and Pathway 3 (explosive release) seed cores are genuinely transient without rotational reinforce 6ment, while Pathway 1 (large-scale rotational aggregation) cores are inherently self-sustaining. Quantitative analysis of DD1 enhancement fractions across ten validated SPARC galaxies provides direct observational evidence for rotational entrainment saturation. GW170817 carrier relaxation at τₒbs ≈ 18. 6 ms is within the range predicted by the substrate framework once the mass-dependent enhancement factor is applied to the vacuum floor τc = 4. 6 ms. Nine popular myths about singularities are systematically addressed. Five falsifiable predictions are presented. 20