Description This publication marks the foundational work of the Dellomonaco Cosmology series, establishing the RMB cosmology framework (Space–Matter–Motion) as a primary theoretical model for cosmic evolution. Instead of postulating a predefined metric background, RMB cosmology interprets motion as the generative process from which effective spatial structure emerges. Matter is understood as stabilized resonant states within this motion–space system, while inertia, gravitational behavior, and expansion arise as emergent consequences of sustained motion–space coupling. This first paper is intentionally non-phenomenological: it does not include parameter fitting, observational datasets, or cosmological benchmarking. Its exclusive purpose is to articulate the ontological foundations and dynamical principles upon which later observational and numerical developments will build. A fully reproducible supplementary package accompanies this article, providing the initial code environment for orbit-based RMB simulations and supporting future extensions of the model. These supplementary materials serve solely as a technical reference for the computational framework — no numerical results are part of this theoretical Paper I.