Path normalization glitch if traversing beyond root

``` erlang
erica_util:normalize_path("/tmp/1/2/3/../../../../../..").
```

results in `"/../.."` where I would expect `"/"` when traversing up to or beyond the root folder.

Start by locating the erica_util:normalize_path/1 entry point and inspect how it handles absolute paths and parent-directory segments. Reproduce the shown input, then verify that traversing to or beyond the root returns "/" rather than a path containing leading parent segments.

Written by the indexing model from the issue text.