Gravitational Manipulation Theory (GMT) v1.0: Boundary-Induced Modulation in a Nonminimally Coupled Scalar–Tensor Framework

Gravitational Manipulation Theory (GMT) v1.0 is a scalar–tensor realization of a boundary-induced gravitational-response modulation framework. A structural scalar field χ, defined through a difference representation D = χ − χ_ref relative to a reference configuration, is nonminimally coupled to gravity through F(χ)R in the Jordan frame and evolves in an environment-induced effective potential W_Ω(χ, ψ, ρ, T). Environmental and boundary conditions select between a normal phase (χ_N = 0) and a modulated phase (χ_G ≃ v_D), separated by domain walls. The paper derives the field equations, constructs a representative symmetric double-wall profile, obtains the induced coupling profile F[χ(z)], and analyzes the resulting localized gravitational response together with its forward and inverse (control) formulations. The framework establishes exact conservation constraints within the stated model: the boundary contribution generates no isolated net gravitational monopole, and covariant conservation excludes reactionless propulsion. It further formulates local stability conditions, scalar-radiation energy balance for time-dependent modulation, PPN / fifth-force screening constraints, and gravitational manipulation as a constrained controllability and reachable-set problem. Physical admissibility and falsifiability are organized through reachability, stability, causality, energy/EFT, and observational constraints. Results are explicitly distinguished as [Exact], [Derived], [Effective], or [Heuristic]. GMT v1.0 does not establish the generation or shielding of gravity and does not support net-gravitational-charge generation or reactionless propulsion. It is a theoretical and effective-model / design framework whose predictions are falsifiable. No experimental implementation or independent validation is claimed in v1.0.