Dark Energy from Conformal Self-Lensing at the T-Symmetric Cosmological Boundary

We derive the time-dependent dark energy equation of state from the T-symmetric cosmological boundary condition, without introducing any new fields, potentials, or degrees of freedom. Structure formation generates Weyl curvature in the bulk, violating the boundary constraint C=0 at a rate proportional to D'=Df. Conformal self-lensing of the boundary's enforcement response by accumulated structure gives an enhancement factor D, yielding total enforcement power P proportional to D³*f². The resulting dark energy density rhoDE = sigma₀ * D³*f²/a produces the equation of state w (a) = -2/3 - f - (2/3) *d (ln f) /d (ln a), with zero free shape parameters. A CPL fit gives w0=-0. 43, wa=-1. 66. Against DESI DR2 (w0=-0. 42+/-0. 21, wa=-1. 75+/-0. 58), the model achieves chi²=0. 02 compared to chi²=11. 2 for LCDM. The model predicts phantom crossing at z=0. 50, peak dark energy density at z=0. 51, parameter-free locking of w (z) to the independently measurable growth rate f (z), and eventual disappearance of dark energy as structure growth freezes. The coincidence problem is dissolved: dark energy is strongest when and only when structure is forming. The cosmological constant problem is avoided: Lambdabg=0 exactly from celestial holography, and the observed acceleration is a transient dissipative effect.