Document DS4 W2 release evidence boundaries

[OmarB97]

Why

The final release narrative must distinguish predecessor qualification from frozen-head validation and make every claim traceable to sanitized receipts without mixing artifact identities. This is isolated from the generated payload so reviewers get a seven-file narrative/index diff.

What changed

• Documents P0/P1/P2 outcomes and the four artifact roles.
• Adds the public evidence index, exact-image source/test receipt, and checksum manifest.
• Updates repository, port, and quality documentation for bounded restaging, manager exclusion, split/base coupling, and the validated 128K boundary.

How to review

Start with docs/benchmarks/ds4-w2-5090-2026-07-11.md, then compare the artifact lineage with evidence/public/ds4-w2-2026-07-11/README.md and exact-image-verification.json. Confirm broader 120/120 and 3/3 claims remain attached to 41d7b2f, while 241ba984 claims only its focused supplement.

Evidence

Combined with upstream receipts PR #8, the checksum manifest verifies all 47 public content files. The complete five-PR union has Git tree dba1a2a613f86a695d23a5c277da877b93c74ac1, byte-identical to the frozen validated donor tree.

Verification

• python3 bench/runner/lint.py — 0 errors, 0 warnings
• python3 bench/runner/render.py --check — up to date
• shasum -a 256 -c SHA256SUMS — 47/47 pass when applied after upstream PR Publish sanitized DS4 W2 release receipts #8
• JSON validation and public privacy scan
• git diff --check

Risks / gaps

• Dependency: upstream PR Publish sanitized DS4 W2 release receipts #8 must merge first because this PR's checksum and links intentionally cover those receipt files. This PR remains draft until Publish sanitized DS4 W2 release receipts #8 lands.
• No throughput claim is added, and live split-FP4 serving quality is not claimed; split mode was validated by the exact-image GPU fixture while the serving sentinel kept it disabled.

Collaborators

• Omar Baradei — operator and final release boundary.
• Codex — narrative reconciliation, dependency isolation, and PR preparation.