Account-pool collision fix requires preservation-fixture and layout budget alignment #7413

Client or integration

Other

Area

Other

Summary

Integrating #7398's existing-clone exclusion exposed two test/document constraints that require coordinated updates. This issue records the failures and fixes rather than dropping them as incidental validation noise.

Reproduction

1. Apply existing native-main duplicate exclusion on eb4bf96.
2. Run codex-preserve-signed-in.test.ts: five cases (around lines 95,143,153,194,211) expect the exact native-main clone copy to remain selectable. Those expectations conflict with [Bug]: Codex pool allows duplicate registration of native main account #7398's new eligibility guard.
3. Add the two regression files to inline scripts/test-layout/layout.json and run file-size-ratchet: the map reaches 2000 lines and is NEW_OVERSIZED.
4. Add collision/routing contract documentation: openai-accounts.md reaches 604 lines against a 600-line budget; structure:check also requires new referenced tests to be staged.

Version

#7398 implementation branch fix/7398-account-pool-usage, base eb4bf96

Operating system

macOS

Logs or error output

file-size ratchet: repository: scripts/test-layout/layout.json, lines=2000, verdict=NEW_OVERSIZED.

Screenshots and supporting files

Resolution in this branch: preservation fixtures use a legitimate separate workspace plan bucket, retaining their original policy assertions (30 pass); new registrations move to layout-codex-collision.json without raising caps; the contract doc stays at 599 lines and referenced tests are tracked. PR will link this ledger. The initially asserted pause-refusal subtype was also corrected to CodexPoolAuthenticationError: refusal was already correct, so no runtime change was warranted for that test expectation.

Checks

• I searched existing issues and documentation.
• I removed secrets, tokens, account details, request credentials, and personal data.

Implementation and evidence ledger: #7414