P7A: A Living-Universe Reinterpretation of the CMB Acoustic Peak Pattern and the Baryon Acoustic Oscillation Feature in the Big Flare-Up Theory Framework

The acoustic peak hierarchy in the Cosmic Microwave Background temperature anisotropy power spectrum and the baryon acoustic oscillation feature in large-scale galaxy clustering are widely treated as among the strongest observational supports of the standard Lambda-CDM cosmological framework. In the standard interpretation, both are fossil signatures of pressure oscillations in a tightly coupled photon-baryon plasma prior to recombination, preserved from a finite-age Big Bang universe. The present paper accepts the observational reality of both features but disputes two claims: first, that these observations uniquely require a singular Big Bang origin; and second, that the BAO scale of approximately 490 million light years is a raw observation rather than a measurement processed through the assumed FLRW expansion history. Within the Big Flare-Up Theory, the universe is spatially infinite, temporally eternal, and dynamically active. The present paper develops a steady-state alternative in which structured spectra arise as long-term statistical outcomes of ongoing shell-like and ripple-like structure generation balanced against scale-dependent damping. A power-balance master equation dP/dt = I - DP yields P(k) = I(k)/D(k) in statistical steady state. Shell geometry naturally generates the oscillatory Fourier factor [sin(kR)/(kR)]^2, providing a mathematically explicit route to BAO-like wiggles without invoking a singular origin. A microphysical layer is added in which Thomson scattering with confirmed cross-section sigma_T = 6.6524 x 10^-29 m^2 and diffusion-like Silk damping continue to operate in present ionised media, with coupling rate Gamma_T = n_e sigma_T c and damping coefficient D_diff = c/(3 n_e sigma_T). These confirm that the same class of microphysics that the standard model invokes as unique to recombination operates in the ongoing universe, materially weakening the uniqueness claim. A current-universe Jeans-length estimate yields a preferred scale within approximately 7% of the observed BAO ruler using only present measured quantities and no assumed expansion history. A concrete CMB-star-formation-rate cross-correlation prediction is derived with formula C_l^{CMB x SFR} = (3 n_e^2 sigma_T^2 / k^2) x b_SFR x P_matter(k), testable with CMB-S4. The paper is presented as a framework and mechanism paper, not a final precision-fit replacement for the standard Boltzmann-code description.