[CI validation only] Core selection

[SaladDay]

Temporary validation of PR #305. A Core-only diff should run hygiene, backend/PostgreSQL and official-client acceptance, while omitting image-only and unrelated browser/native work. Do not merge; this PR will be closed after recording the result.

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[blacksmith-sh]

Found 1 test failure on Blacksmith runners:

Failure

Test	View Logs
github.com/MiniMax-AI/OpenAgentCore/services/core/internal/execution/ TestFailedInventoryRetirementClosesAdmissionAndRetainsGate	View Logs

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