Future–Mass Projection (FMP): Formalism, Solar–System PPN Safety, and Gravitational–Wave Speed

We present a compact and testable formulation of Future–Mass Projection (FMP), a time–nonlocal gravity response in which the present metric couples to standard baryons plus a causal projection of future baryonic configurations. We derive the weak–field and PPN mapping, proving that FMP can satisfy the Solar–System bounds on the Eddington parameters γ and β as well as the tight limit on G˙ /G. In linearized, source–free vacuum the wave equation remains □¯hμν = 0, hence cGW = c, consistent with multi–messenger observations (GW170817/GRB 170817A). We provide a practical (μ,Σ,W) kernel parametrization that is PPN– and GW–safe by construction, list working priors for data analyses, and sketch cosmological aspects via the homogeneous ratio R(z) ≡ ΩF /Ωb.