The lineinfile task appends the source line to `~/.bashrc` but never declared `create`, so it aborted with "Destination
does not exist" whenever that file was missing. This hits every user configured with `create_home: false`, and it hit
every btrfs user as well, because their home is an empty subvolume and useradd therefore skips the skel rollout.
`mode` is added along with it, otherwise a newly created bashrc would inherit whatever the umask happens to be. The
existing `owner` and `group` were dead settings until now, since the file was never created by this task.
Co-authored-by: Copilot <copilot@github.com>