Trace ambiguous workflow-to-CHASM ownership

[chaptersix]

Problem

A committed CHASM create can lose its response. V1 treats the error as permission to execute the
copied work, then accepts any later AlreadyExists as successful migration without verifying
destination ownership or snapshot freshness.

Minimal reproduction

One fixed-time V1 scheduler holds one manual ALLOW_ALL start. The test commits its migration
snapshot and returns Unavailable. V1 starts the same action using a different request ID. With
the rollout flag enabled, retry closes V1 after an unverified collision; with it disabled, V1
continues while CHASM remains present. All four version 12/13 and flag combinations fail.

The causal trace and operational disposition are commit-pinned in
the forward handoff note.

Disposition

No scheduler-only production fix is submitted. Freezing V1 after an ambiguous create is necessary
but cannot safely complete migration while History can still acknowledge source signals. The
required ingress-fenced staged protocol is documented in #44. Migration must remain disabled until
that prerequisite exists.

Validation

TEMPORAL_RUN_MIGRATION_COUNTEREXAMPLES=1 go test -tags test_dep \
  ./service/worker/scheduler \
  -run 'TestMigrationCounterexample_(LostCreateResponse|ForwardDestinationCollision)' -count=1

Stack

• Parent protocol: Document required scheduler migration handoff protocol #44
• This PR: forward ownership trace
• Next: Document scheduler migration signal fence gap #48 signal admission fence

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-05T01:02:45.304515Z	7d2d91b	Draft marked ready

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