Unquoted xargs pipeline in driver error path

## Severity: HIGH

## Location
- `ralph/ralph_loop.sh:191`

## Description
The error message for a missing driver uses `xargs` without `-0`, susceptible to filename-based injection. Combined with the `RALPH_DIR` override, crafted filenames could inject content into the pipeline.

## Suggested fix
Replace with a safe glob loop using `basename` directly.