Run the chosen sync engine with PHP WebSockets on WPVIP

## What happens now

The candidate sync engine and PHP WebSocket transport have not yet been validated together in a production WPVIP environment.

## What should happen instead

Run a controlled production validation and record the safety limits, measurements, failures, rollback plan, and findings.

This depends on choosing the candidate engine. This is a stub and still needs a real example, completion checks, and implementation notes.