feat: improve remote home directory resolution for mounts

Enhances SSHFS mount reliability by improving remote home directory ('~'
path) resolution.

- 'lua/sshfs/lib/ssh.lua': Implemented 'Ssh.get_remote_home' to fetch
  canonical remote home paths using 'readlink -f $HOME || echo $HOME'.
- 'lua/sshfs/lib/sshfs.lua': Refactored mount logic; 'mount_via_socket'
now to now use 'Ssh.get_remote_home' to resolve '~/...' paths before
mounting.
- 'lua/sshfs/ui/ask.lua': Updated 'normalize_remote_path' to pass
through '~' paths, relying on the new resolution mechanism in
'sshfs.lua'.

This ensures accurate handling of symlinked or non-standard remote home
directories.

Ref #8