chore(mods): accept default-closed instance control transport

[ShuhaoZhangTony]

Summary

• repin the canonical dev-hub producer from e7d1525 to 733268f
• accept and verify the default-closed vllm-hust.instance-control/v1 contract
• require the pinned owner binding to validate the generic control manifest and entrypoint
• document the single-writer boundary and remaining production-backend/host-authority gates

Safety

• no production instance is registered
• productionBackendQualified remains false
• no .env, systemd, container, engine, proxy, NPU, or broker state is changed
• missing host authority returns an explicit closed status and creates no controller database

Validation

• Sage owner/control contracts: 117 passed
• dev-hub transport/transaction/foreground/authority/broker contracts: 101 passed, 47 subtests passed
• post-commit exact-gitlink smoke: 4 passed
• Ruff and git diff --check: passed

This is protocol acceptance and thin binding only. It is not evidence that a production Mod is active or that the shared inference instance has been enrolled.