De Tempore Luminis Einstein's Forgotten Equation — c is the Speed of Time, E=mc² is the Equation of Time

For 120 years, physics has interpreted E=mc² as a relation between matter and light {Einstein1905}. We present the final consolidated manuscript of TER v4.0, De Tempore Luminis, where we prove that this interpretation is ontologically incomplete. We propose the Time-Light Equivalence Principle: c is fundamentally the speed of time vT = 299,792,458 m/s, not the speed of light. Light is time made visible at vT. Mass is condensed time MT, Energy is energy of time ET. The master equation ET = MT · vT² ≡ E=mc² is identical numerically to Einstein's equation but reveals its true meaning: it is the equation of Time.