perf(state): reuse retained proof for native worker opens (#154258)

perf(state): reuse retained proof for native worker opens (#154258)

Transfer revocable host integrity proof after ordinary handle close through the existing native admission port. Keep receiver identity validation and durable verification gates intact. A synthetic 1 GiB database opens in 12 ms median versus 96 ms; Testbox regression, sibling tests, changed checks, and independent review pass.