Make replicate error message less confusing

[nodo]

At this point in the logic, errors could be caused by network issues, context cancellations, etc. Using sync wouldn't fix those errors.

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Note

Low Risk
Low risk: changes only the wording of an error message and does not affect replication logic or data handling.

Overview
Makes replicate failure reporting less misleading by removing the trailing “use sync instead” hint when executeReplicate returns an error, while keeping the existing relay-capability checks and their guidance intact.

^{Reviewed by Cursor Bugbot for commit ae25c6d. Configure here.}