suprsync: Add debug line for rsync command

[BrianJKoopman]

Description

This adds a debug line for showing what rsync command is running to do the sync.

Motivation and Context

One of the suprsync agents on satp2 is transferring with incorrect permissions and I'm trying to debug what's going on. This will at least help confirm what command is being run so I can check for any issues there.

How Has This Been Tested?

I've run this on the E2E testing system. Here is an example log with the LOGLEVEL=debug and the autobahn heartbeats removed:

2026-01-21T16-03-49.204589 Copying files:
2026-01-21T16-03-49.204777 - /mnt/nfs/data/ocs3/temp_data/timestreams/17690/emulator1/1769011239_000.g3
2026-01-21T16-03-49.205168 - /mnt/nfs/data/ocs3/temp_data/timestreams/17690/emulator1/1769011228_000.g3
2026-01-21T16-03-49.205507 - /mnt/nfs/data/ocs3/temp_data/timestreams/17690/emulator1/1769011215_000.g3
2026-01-21T16-03-49.205766 Running: rsync -Lrt -p --chmod=g+rwX,o+rX /tmp/tmpjkve57o3/ /mnt/nfs/data/ocs3/timestreams
2026-01-21T16-03-51.939120 Checksumming on remote.
2026-01-21T16-03-51.940139 Running: md5sum /mnt/nfs/data/ocs3/timestreams/emulator1/1769011239_000.g3 /mnt/nfs/data/ocs3/timestreams/emulator1/1769011228_000.g3 /mnt/nfs/data/ocs3/timestreams/emulator1/1769011215_000.g3
2026-01-21T16-03-51.953818 Copy session complete.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.