PART 28A: BLACK HOLES AS TRANS-SECTOR PHASE-COLLAPSE DYNAMOS IN DUAL–H₄ GEOMETRY

Within the framework of Origin Geometry (OG), effective spacetime is described as a discrete topological-geometric network comprising a visible sector (H₄) and an orthogonal dark sector (φH₄), separated by an effective phase-accessibility barrier. Previous works have investigated electromagnetic suppression within the dark sector, inter-sector leakage near regions of extreme curvature, topological pinning, bulk relaxation, and effective gravitational-wave-like excitations. In Part 28A, we synthesize these mechanisms into a unified dynamical framework tailored for extreme gravitational environments. We investigate the proposition that black holes act as effective *phase-collapse regions* within the dual-H₄ network. In these regions, extreme phase compression diminishes the isolation between the two sectors, enabling bidirectional topological tunneling. The central conceptual mechanism introduced in this work is the *phase-stress gradient*—a geometric manifestation of phase-structure deformation under extreme curvature. When the inter-sector phase barrier is heavily compressed, visible matter may partially tunnel into the φH₄ sector, while dark-sector excitations may simultaneously leak into the visible H₄ sector. Upon entering the dark sector, transferred visible excitations may interact with phase-conjugate defects, triggering an effective topological cancellation process. The energy released from this cancellation does not primarily thermalize into boundary electromagnetic modes; instead, it preferentially couples to the collective bulk modes of the underlying geometric network. The continuous cycle of accretion, phase compression, cross-sector transfer, topological cancellation, and bulk relaxation constitutes an effective energy conversion engine that we term the **Trans-Sector Dynamo**. Under this paradigm, black holes do not act exclusively as terminal gravitational absorbers. Rather, they can simultaneously function as collective sources of bulk geometric excitations, which, at a coarse-grained macroscopic level, may manifest as high-frequency gravitational-wave-like signatures. This Part does not attempt to construct a complete continuum field theory for these bulk modes, nor does it seek to replace the standard General Relativistic model of black holes. Instead, it proposes a novel topological-dynamical mechanism to model energy transfer between boundary dynamics and bulk geometry within the dual-sector architecture of Origin Geometry.