This work presents a theoretical formulation in which the quantum vacuum is interpreted as the hydrodynamic ground state of a conserved temporal continuum governed by a continuity law for temporal density. The invariant relation ∇μ(ρ_t v_t^μ) = 0 is taken as the fundamental conservation principle, from which the structure of vacuum fluctuations, mode density, and gravitational coupling are derived. Within this framework the vacuum is not treated as empty space but as a dynamical medium characterized by temporal density and temporal flow. The theory is constructed from a variational action in which the continuity law is enforced directly, producing field equations that couple temporal dynamics, informational degrees of freedom, and spacetime curvature in a single consistent system. In uniform temporal backgrounds the formulation reproduces the standard results of quantum field theory, including the Casimir effect and the known scaling of vacuum energy. In non uniform temporal flow the theory predicts controlled corrections determined by temporal shear, vorticity, and density gradients. These corrections provide experimentally testable signatures in superconducting cavities, atom interferometry, and Casimir Polder measurements. The resulting stress energy tensor, field equations, and vacuum energy expression form a mathematically closed description in which vacuum structure, inertia, and gravitational response arise from the same conservation law. This approach provides a hydrodynamic interpretation of the quantum vacuum that is compatible with relativistic covariance while allowing new experimental probes of vacuum structure. This manuscript is a revised 2026 version of work originally published in 2025 and forms part of the Chronoflux research program, which investigates the possibility that spacetime geometry and quantum behaviour emerge from conservation laws of an underlying temporal medium.