Detection Ontology, Part 1: Existence ⇔ Detection — The Ontological Axiom and the Lambert-W Structural Constant

We establish the foundational axiom of the Detection Ontology: Existence is equivalent to Detectability. A system exists if and only if it participates in a recursive self-detection loop that distinguishes it from the void. We formalize this via the Universal Seesaw Stabilizer, now realized inside the Parameterized Spectral Unification Framework (PSUF). The stabilizer is a real, even spectral triple embedded in the Universal Spectral Object 𝒰 = Spec(𝒜), where the algebra 𝒜 is θ-twisted and the coupling is mediated by the Wide-Net block matrix. We prove that stability of this coupling requires the Lambert-W structural constant θ_eff = W(1/√(4π)) ≈ 0.225209973392 (the physics-specialized fixed point of the resonant-critical regime). This value is the unique solution that prevents chaotic divergence in the spectral flow, thereby ensuring the existence of a stable, three-generation universe. The Wide-Net seesaw reduction supplies a rigorous Schur-complement positivity proof that replaces earlier bounded-perturbation arguments.