```python
def crumb_split(trail: str) -> list:
    """Split a breadcrumb trail on forward slashes and discard every empty segment."""
    return [segment for segment in trail.split('/') if segment]

def crumb_join(parts: list) -> str:
    """Join segments back with a single slash between them and no slash at either end."""
    return '/'.join(segment for segment in parts if segment)
```