Rework the default /workspace layout into a three-column view
with a left-side Workbench, centered terminal, and right-side
status monitor.
Add a new Workbench pane that groups file manager, command
history, and editor into tabs while preserving panel state.
Extend server status data to expose cumulative network upload
and download totals since boot, and show them in the monitor.
Include a lightweight migration for the old default layout and
update related locale strings, pane metadata, and knowledge
base records.
Publish frontend, backend, and remote-gateway images to GHCR on
pushes to main and manual runs. Also update docker-compose to pull
the three service images from ghcr.io instead of Docker Hub.
yinjianm