Tyrell Build 13 release rereview v5

Completed the final independent source release gate against the frozen Build 13 revision and issued a GO for build/sign plus the required rdmbair15m5 canary; fleet expansion remains runtime-receipt gated.

• Scope: local rdmsm4x read-only review; no remote host, application runtime, signing identity, or deployment changed.
• Source reviewed: /Users/richh/dev/_worktrees/tyrell-build18-chat-catalog-20260902 at base HEAD 42277bcf045b3e9d6b93ac2ab98355db08c89d56, dirty diff SHA-256 0836121d461aad03c75b1e59553b77e6beb21ce1b6d01a12e6ab53c8d1435217.
• File added: /Users/richh/dev/_handoff/tyrell-build13-release-rereview-v5-20260903.md (SHA-256 6715f81ef834ad30c0cd62206ef34fcc74be3c3bef055ffdc05d9beb81314fa6).
• Project files touched by reviewer: none.
• Validation: syntax over all scripts/libraries/script tests; all eight release contracts; headless debug build/lifecycle; nested-status executable matrix; git diff --check; prior full Swift log hash verification. All passed.
• Decision: no P0/P1 source transaction blocker remains. Only helper statuses 3 and 4 compose with exact outer recovery; status 5, unknown failures, and signals remain incomplete. Helper PID/job ownership, signing identity, candidate recovery, accepted-current evidence, and rollback preservation gates are intact.
• Undo: remove only the v5 handoff report and this changelog. No source/runtime rollback is required.
• Outstanding owner action: build and sign the frozen candidate, deploy only to rdmbair15m5, collect exact app/helper/runtime/usage/chat/receipt and rollback evidence, then expand the fleet only after that acceptance passes.
• Apple Notes: pending because this reviewer runs under the Background launchd manager and cannot safely send GUI AppleEvents.