[jmbarrancoml]

I prove a raw-prefix refinement for the selected coefficient boundary: keep the physical header g, compute g sigma B0 in control, and pull the prepared coefficients back through the induced affine high-cube bijection. The caller can preserve raw-header order and complete packets. I extend the substitution over the fixed-low residual trace under the retained normal-form and completed-child contracts.

I implement canonical generated-field counters and serialize the field schema, program and pending/value stacks. At a selected head-ADD site, I derive the current coefficient from its raw field and evaluate incoming weights from older global slots. I keep arbitrary spectator metadata outside those scans and recompute the coefficient for the inverse pass. This addresses the header-order and preparation-to-stream interfaces left by PR2332 and PR2364.

I passed the registered Python 3.12 normal and optimized replays:

• Complete two-dimensional Z/9 high cube: 81 matrices, 6,561 opaque records and inverse restoration.
• Actual selected COPY510 and nonidentity-owner MOVE fixtures, plus a joined generated-weight site with coefficients 4,7,1 and 1,944 records in its reduced finite rectangle.
• Four serialized mixed/reset chains, 36 coordinate comparisons and identical local symbol counts under translated origins, replaced buried data and larger spectator metadata.

The selected64 fixtures cover snapshots and reduced site rectangles. I retain host arithmetic, decoded local operands, finite source dispatch and loop bounds as macros. The uniform local charge uses the written lowering and PR2310's conservative allowance. Reviewers still need to connect the selected global family/owner interpreter and check the remaining operational lowering. I claim no full GL64 payload execution, new formalization or exponent improvement, and I leave the selected frontier unchanged.

python3.12 scripts/research_package.py --package research/selected-prefix-coefficient-site

Review PROOF.md and the explicit measurement boundary in README.md. Coordination and scope: Discussion2319 follow-up.

I credit @commdata2338's actual selected table binding in PR2332 and concurrent request-bound and callee-substitution results in PR2386/2399. I retain the earlier source527, selected supplier, normalizer/descriptor, fallback, stream and marked-tape contributions in NOTICE.md; this is no first table-encoding or stack-algorithm claim.

Jose Manuel (jmbarrancoml), with substantial OpenAI Codex assistance. No independent human review claimed.