Combine --node-name with --threads #119

docs/native-engine.md ("Not yet"): "No threads: --node-name can't be combined with --threads."

So a multi-node deployment cannot also use worker threads for fault and CPU isolation. The two features are orthogonal in intent and should compose.

Do

• Make the owner resolver consider both the local thread shard and the remote node.
• Ensure a thread crash and a node takeover interact correctly (a thread replacement must not look like a node loss).
• Add a test that runs --node-name with --threads 2.

Done when

The combination starts, forwards correctly, and survives a thread crash and a node restart.