* Backport OSSMC frontend sync workflow to v2.11.

Dispatch openshift-servicemesh-plugin sync on frontend pushes to
release branches using the v*.* branch filter.

* Pin goimports to v0.47.0 for Go 1.25 compatibility.

goimports@latest now resolves to golang.org/x/tools v0.50.0 which
requires Go >= 1.26, breaking CI on release branches with GOTOOLCHAIN=local.