How Gauge-Field Proxies Emerge for a Finite Observer in a Closed Reversible 1+1D q=3 Universe: Object Boundaries, Curvature, and Epistemic Firewalls

Modern foundational physics often begins by assuming spacetime and fields before the observer enters the story. Here we reverse that order. We study an explicitly prespecified 1+1D closed reversible computational substrate—a periodic q=3 ring evolved in discrete reversible time—and ask what a finite internal observer can reconstruct without oracle access, lookup tables, or nonlocal shortcuts. Within this setting we recover operational proxies for object boundaries, finite gauge quotients, localized holonomy residuals, curvature-mediated scattering, inverse scattering tomography, noisy curvature-field reconstruction, dynamical backreaction, and a minimal effective equation. The key interpretation is informational rather than ontological: field-like structure appears as the minimum-description-length compression strategy available to a bounded observer confronting reversible microscopic dynamics. The validity of the resulting effective description is controlled by a finite capacity wall, summarized by the order parameter phi = Cᵢnf - sigma: positive phi supports transfer, zero phi marks a finite critical edge, and negative phi requires ambiguity or rejection. A machine-audited no-go layer rejects continuum-limit overclaim, arbitrary refinement, quantum error correction, Yang-Mills identification, lookup-table memorization, oracle access, nonlocality, and other illicit upgrades. The result is not a derivation of continuum physics. It is a finite theory of disciplined emergence: on a prespecified 1+1D reversible substrate, effective gauge-field proxies can arise for an internal observer, and their honest boundary can be drawn sharply.