R3 gate #51: BinaryDimensionReportEquals constant-fold witness (#2575)

[briansrls]

Summary

Completes #2575 consumer acceptance on top of main after #2577 (SymbolicCostExprEquals baseline) and #2578 (gate #52 host receipt):

• Fixture r3_free_consequences_second_batch.dag: gate Lane a p12 to p6 #51 uses BinaryDimensionReportEquals with distinct workflow roots fold_pre (1 + 2) vs fold_post (3).
• test_runner.rs: eval_r3_gate51_cross_target_constant_fold_binary_dimension_report_equals — structural fold witness via Int-add OperatorRealization.cost (must match across rust/python/go), then cross-target Type(Int) realization overlay on the normalized pre bound.
• Integration tests: suite shape assertions + cross_target_optimization_constant_fold_consistent_has_symbolic_cost_witness; merged with gate Extend minimal execution model to all tool workflows #52 receipt test from [codex] Add gate 52 structural cost receipt #2578.

docs/r3-program-plan.md §1.8 row #51 updated: retire stale #2582 reference; note #2577 baseline + this follow-up.

Not claiming r3-structure.md certification-corpus-wide PASSING (still deferred per issue / ledger).

Fixes #2575

Made with Cursor

[briansrls]

Dashboard triage (PR feedback bundle — no discrete review threads on GitHub)

Verified against current session/smart-cat-457 @ 7ad588a1d (checked out in this worktree):

• cargo test -p v3-compiler r3_free_consequences_second_batch — 3/3 pass (suite + gate Lane a p12 to p6 #51 witness + gate Extend minimal execution model to all tool workflows #52 receipt).
• cargo clippy -p v3-compiler --all-targets -- -D warnings — pass (ctrl-build remote run).

GitHub API / UI snapshot: REST pulls/2584/reviews is empty; pulls/2584/comments (issue comments) is empty; no review line-comments returned. There is no actionable reviewer finding in GitHub artifacts to fix in a follow-up commit from this pass.

CI (gh pr checks 2584): fmt pass, ci pass, v3 still pending on workflow 25624546364 — not “CI green” end-to-end yet.

Merge readiness (your bar): Not met — need v3 success + ≥2 distinct approving api-review artifacts (e.g. codex + openai-pro, per org policy) + no REQUEST_CHANGES. mergeable is MERGEABLE (no conflicts) but mergeStateStatus is BLOCKED until required checks/reviews clear. No gh pr merge --squash from this agent until those land.

— sent from smart-cat-457

[briansrls]

Review metadata

• Provider / model: codex / unknown
• Commit: 7ad588a1 · Trigger: schedule
• Thinking: 347s wall

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Non-blocking — Strengths

• src/v3/compiler/src/test_runner.rs Gate #51 stays implementation-scoped, fails closed on malformed claim/report/realization inputs, and does not introduce substrate state.

ROADMAP — Verified

• cross_target_optimization_constant_fold_consistent: Row #51 keeps CONSUMER_LANDED partial status and explicitly defers PASSING until certification-corpus evidence exists.

✅ No blocking concerns in the mixed code, fixture, and planning-doc changes.

[briansrls]

Superseded — gate #51 already landed via #2577 (merged earlier today). This PR was opened after the work item closed. Closing as duplicate. — wise-bear-525