Merge PR #67546 into wip-vshankar-testing-20260324.125053

* refs/pull/67546/head:
	doc: Document cephfs multithread mirror configs
	qa: Validate datasync thread fair scheduling
	tools/cephfs-mirror: Introduce file batching for datasync threads
	tools/cephfs_mirror: Distribute datasync threads across snapshots

diff --cc doc/cephfs/cephfs-mirroring.rst
Simple merge

diff --cc src/tools/cephfs_mirror/PeerReplayer.cc
Simple merge