This proof paper proposes a novel generalization of the rest-energy relation, E=P[mc² + AI/τ], where P is a projector implementing prime-indexed discrete scaleinvariance (p-DSI), τ > 0 is a chronofluid relaxation time, I is an informational action (units of action), and A is a dimensionless agency coupling. Starting from E = mc2, we model the background as a Maxwell-type temporally viscous medium; linear-response yields an energetic channel proportional to I/τ. We formalize the prime-lattice dilation group with dilations λp = pα and define P as a Cesaro-weighted average over primes that projects observables onto the p-DSI-invariant sector. While not (yet) established physics, the proposal is a structured conjecture amenable to falsification through relaxation sweeps and discrete-scale forcing experiments. In other words, Einstein was not wrong: E = mc2 is a special case valid when prime defects are negligible and the fluid of time is extremely thick