fix: Run backup/restore on host via nsenter for Python venv compatibility

Host Python venvs (3.12) cannot run inside the container (Python 3.11).
Added run_ops_host/stream_ops_host in ops_runner.py that use
docker run --privileged --pid=host alpine nsenter to execute ops
commands in the host namespace. Applied to backup and restore flows.

	app/app/ops_runner.py	diff | view | blame | history
	app/app/routers/backups.py	diff | view | blame | history
	app/app/routers/restore.py	diff | view | blame | history
	app/ops_runner.py	diff | view | blame | history
	app/routers/backups.py	diff | view | blame | history
	app/routers/restore.py	diff | view | blame | history