Feature Request: `--oneline` mode for `--tree`

When I do

`❯ command lsd --tree --almost-all --icon never`, I get

```
.
├── bar
│ └── baz
└── foo
```

The same exact output when I add the `-1` option.

It would be great if `--tree -1` would give

```
bar
bar/baz
foo
```

Start by tracing how the Rust CLI handles the --tree and -1 options, including the code that formats tree paths. Confirm the existing output with the command from the issue, then make --tree -1 produce one path per line as shown for bar, bar/baz, and foo.

Written by the indexing model from the issue text.