OptimizedNodeBridge should enforce protocolVersion via meta handshake

[bbopen]

Problem

OptimizedNodeBridge does not validate the Python bridge’s protocol version. If the Python subprocess is mismatched (older/newer protocol), OptimizedNodeBridge will still send requests and attempt to decode responses, potentially producing silent misbehavior or hard crashes. NodeBridge guards this via meta validation; OptimizedNodeBridge does not.

Evidence

• src/runtime/optimized-node.ts: no meta call or protocolVersion validation during init or worker spawn.
• src/runtime/node.ts: refreshBridgeInfo() validates protocol and protocolVersion.

Acceptance criteria

• On worker spawn (or at init), call meta and validate protocol + protocolVersion.
• On mismatch, terminate the worker and surface a BridgeProtocolError.
• Add a test fixture with mismatched protocol version to ensure OptimizedNodeBridge rejects it.

[bbopen]

🔄 Duplicate of #82 (now resolved)

This issue describes the same protocol version validation requirement as #82. Both are now resolved in PR #136 - the unified NodeBridge calls validateBridgeInfo() during initialization.