Causality-Preserving Retro-Observation via Controlled Fundamental Metric Deformation

A hypothetical entity can exclusively deform the fundamental metric gμν locally. We prove (Theorem 3.1): Through h ∈ C∞0 (R) with ∥h∥C0 < ε an event E /∈ J−(O, g) is brought into J−(O, g′), without CTCs. Proof: global Fermat principle, direct method in H1, time function t ∈ C1, Raychaudhuri equation, Whitney-C0 openness. Dynamically: massive local NEC violation. Causality is preserved.