ADR-053/R6.2: execute and archive the native macOS D-3/D-6 memory proof

[MikeRoss27]

Context

ADR-053 / ENG-MEM-001 is implemented and measured on Windows and Linux. The local gates and crash-consistency kill-loop are green, but R6.2 must remain open until the same oracle runs natively on macOS.

Required evidence

• Run cargo xtask test-r6-memory on a native macOS runner for the final implementation commit.
• Capture the bounded and negative-control JSON reports, all child logs, and provenance.
• Verify the Darwin sampler uses public proc_pid_rusage(RUSAGE_INFO_V4) and records ri_phys_footprint / ri_resident_size.
• Confirm every allocation category stays below its analytical budget and the negative control is detected.
• Archive SHA-256 hashes and the CI/runner metadata in the ADR-053 proof document.
• Re-run cargo xtask test, cargo xtask check, and cargo xtask test-crash-consistency for the final integrated commit.

Current local evidence

• Commit: ea47045
• Windows and Linux normative reports: docs/benchmarks/n13-r6-adr053-memory-proof-2026-08-01.md
• Cross-compile check: aarch64-apple-darwin succeeds; this is not a native execution proof.

Definition of done

Close this issue only when the macOS reports are attached and the ADR proof document records the exact commit SHA, runner, commands, exit codes, category maxima/extents, and report hashes.