A closed scale : from the Planck vacuum to the meV condensate

The cosmological constant Λ is measured but not predicted. This preprint demonstrates that a single measured input closes the Planck scale in form. A tautological identity relates the de Sitter horizon to the Planck scale exactly, R_dS/l_P = (m_P/m)²·√(3/8π), where m = (ρ_Λħ³/c⁵)^{1/4} is the unique mass constructible from the vacuum. A quartic lock, Λ = 8πGm⁴c/ħ³, relates Λ to the mass of a condensate; the scale kernel x = Λ·l_P² reads three times as a square (wall, seed, throat) and reduces the edifice to a rank-1 monomial with no free parameter. The chain imposes a particle at m = 2.2479 meV, a spectral address at ν = 543.5324 GHz, a black-hole–condensate pair (M* = 4.7034×10²¹ kg), and a closure mass M_total = 1.1091×10⁵³ kg whose horizon is exactly the de Sitter horizon. The form is demonstrated at machine zero (18 identities, 12 mirror inversions, independently re-verified from CODATA values alone); the value is written by no equation — a theorem verified over 2.8 million monomials. This deposit is an act of preregistration. The four-branch decision tree recorded on 20 October 2026 is reproduced in Section 7: (1) a boson detected at 2.2479 ± 0.0046 meV (≈ 543.53 GHz) would measure the de Sitter entropy to ±0.0041 and reconstruct Λ to 0.8 %; (2) detection at 5.26 meV would confirm the dark dimension while invalidating the mass identification; (3) detection elsewhere would reduce the quartic alignment to coincidence; (4) no detection after band exhaustion would not refute the corpus (compatible with full coupling freeze). A null signal does not rule the prediction out; a non-null signal settles it.