Quasistatic Aether-Scalar-Tensor Gravity: Galaxies, the Solar System, and Non-Linear Steady States of Dwarf Galaxies in an Aether Wind

Paper I of the Trifurcation series (October 2026). First public version. It replaces unpublished drafts of 29–30 September 2026, which are withdrawn. The paper's last section lists what was removed: a solver table no solver produced, a numerological link to Paper II, an inconsistent quasistatic equation, an over-described and mis-evaluated a0, an inverted Crater II comparison, and a +13.4σ high-redshift claim. The paper collects the quasistatic phenomenology of the Aether-Scalar-Tensor (AeST) theory of Skordis and Złośnik with μstd(x) = x/√(1+x²), and reports what holds and what fails. The quasistatic limit is an AQUAL-type pair of channels. The kinetic function giving μstd is derived by calculus and checked in Lean 4. In spherical symmetry the two channels reproduce the single-field law only as λs → 0. SPARC (171 galaxies, 3,375 points): the anchor a0 = cH0/2π and the literature value tie when per-galaxy nuisance parameters are fitted (median χ²ν 3.36 and 3.41). Without them the literature value fits better (11.08 against 9.93). The anchor is a declared input, not a derivation. Solar system: on AeST's held branch, the Milky Way's external-field quadrupole for bare μstd is excluded by Cassini (4.6σ; 8.4–8.7σ against the 2026 bound). New: a C¹ finite-element solver for the weak-field steady-state AeST equations of a dwarf galaxy in an aether wind. Of its pre-registered gates, five pass and two fail, and both failures are reported. Converged solves at 100–300 km/s are stripped of their MOND field, and within 0.6 kpc the Newtonian channel carries general relativity's normalization 1 − KB/2. The remnant falls with box size and is not converged in it. Exploratory, at KB = 1/2, 𝒦2 = 75 and Q0 = 0.1/Mpc only. High-redshift a0 is inconclusive. AeST's CMB fit is reported by its authors, not verified. Files. 1_…_alien-codex.pdf: dark display edition. 2_…_journal.pdf: light journal edition, same content. …_source.zip: LaTeX source and style file. …_code_and_evidence.zip: the two scripts written for this paper with their outputs, and evidence files exported from the public Res-Nova repository (main @ c3ff5f3; branch d7-stage2-solver @ 739e483). MANIFEST.txt gives each file's source and SHA-256. Epistemic labels used in the text: [P] proved in Lean 4; [D] derived, including computation; [C] cited result; [E] empirical; [conj] conjecture; [O] open; [X] withdrawn or excluded. AI systems assisted with derivations, code, numerical runs and drafting under the author's direction. The author reviewed every claim against the files in this deposit and takes full responsibility for the content.