Lorentzian Signature as the Stable Informational Valley: Why Spacetime Has the Metric Signature It Does

Proposition with FRG Pathway: Lorentzian signature is the unique stable attractor of spectral contraction dynamics on the informational manifold. Non-Lorentzian metric deformations decay at rates set by the spectral gap field; Lorentzian signature is the survivor. This addresses why physics is Lorentzian rather than Euclidean or Carrollian as a structural consequence rather than an empirical postulate. Pathway: completion via FRG fixed-point classification (Saueressig 2024 program). Inherits from Paper 0 (axioms A2, A3, A6).