Order-3 BigRational jet AD (no symbolic algebra): Fisher–Rao + drift-flip
metric, Γ/R/∇R/R·R/Q(g,R) at rational points. Validated against the sympy
Δ₃ ground truth (exact match incl. (∇R)_(0,0,1,0,1)=1987584/1500625 and
the drift obstruction scalar). Signature via congruence elimination
(Sylvester's law of inertia) — fixes a row-aliasing bug that reported
(4,3) at the Δ₇ centroid; truth is (6,1), numpy-confirmed.
Δ₇ centroid results (31s single-core): baseline constant curvature 1/4
holds; g' signature (6,1) with drift time-like (g'(β,β)=−35); verdict
PROPER (11076/16807 nonzero ∇R, 591 inconsistent L ratios) — matches Δ₃.
survey subcommand = resumable DAG: one receipt JSON per lattice point
(skip-if-exists), rayon-parallel, --max-points deterministic stride cap;
receipts are ingestable scar-map events (obstruction ⇒ scar candidate).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
