Conformal Primacy: Mass-Clock Redshift and Horizon Entropy from a Single Weyl-Scaling Postulate

We present a conformal-primary interpretation of Friedmann-Lemaitre-Robertson-Walker (FLRW) cosmology in which conformal structure is primary and metric geometry is a Weyl-scaled overlay, gµν = a2(η)gµν, a= A−1 FLRW. Conventional expansion, AFLRW →∞, then corresponds to contraction of the metric overlay, a→0, relative to a fixed conformal substrate. The framework introduces no new particle, force, or free parameter. Its central idea is a single Weyl/mass-scaling postulate. Universal mass scaling mi ∝a−1 yields the mass-clock redshift dictionary 1 + z= a(te)/a(t0). Because MP ∝a−1 implies ℓP ∝a, the same postulate makes the dimensionless ratio A/ℓ2 P conformal-frame invariant, so that horizon and Ryu-Takayanagi/HRT entanglement entropies stay well defined as the metric overlay collapses. The redshift and entropy sectors are linked by the same assumption. Supporting results include exact area/volumescaling, A/V∼a−1, Einstein-equationpreservationasframeequivalence, hierarchy-ratio stability, a registration-filter mechanism that can protect the Higgs from unsuppressed Planck-scale sensitivity, and background observational dictionaries for Type Ia supernovae, CMB distance priors, and recombination. The same registration logic also identifies a conditional open route to the dark energy hierarchy: if the leading metric-registered dark-sector density is tied to the fixed asymptotic de Sitter boundary scale, Λeff = 3/ℓ2, then ρreg de = M2 PΛeff = 3M2 P/ℓ2 rather than a raw substrate Planck density. The observed suppression becomes ρreg de /M4 P = 3/(ℓ2M2 P) = 3(ℓP,0/ℓ)2 ∼10−120. The derivations supplement records the linear tight-coupling map for photon-baryon acoustic oscillations and a leading rapid-contraction template for primordial initial conditions. Claims are organized into exact identities, interpretive postulates, and completion targets. Quantum measurement is developed as metric registration. In the measurement sector the primitive action is the registration action Sreg, the expression rule by which substrate code becomes a metric record. The companion paper establishes, conditionally, no-signaling and the Tsirelson bound for the registration kernel from reflection positivity of a conformal substrate two-point function. Microscopic entropy degeneracy, dark-sector dynamics, representation content of Sreg, and the observed scalar tilt and full CMB spectra from substrate-derived initial conditions remain completion targets.