## What changed?
<!-- Describe what has changed in this PR -->
Added a background routine to `matching/nexus_endpoint_client` which
checks whether the last known table version has changed.
## Why?
<!-- Tell your future self why have you made these changes -->
In rare cases, when a new node acquires ownership it may miss in-flight
updates from the previous owner and has no way of detecting this
inconsistency.
## How did you test it?
<!-- How have you verified this change? Tested locally? Added a unit
test? Checked in staging env? -->
Existing tests
