Fixes the issue reported in PR #410 where mo purge fails to find
artifacts when fd returns empty results.
Changes:
- Implement MO_USE_FIND environment variable to force using find
- Improve fd fallback: check if fd output is empty (-s test)
- Add debug logging to show which tool is being used
- If fd returns no results, fallback to find automatically
This fixes the root cause where fd successfully runs (exit 0) but
finds nothing, preventing the find fallback from being triggered.
- Replace parentheses with commas for supplementary info
- Use commas instead of em-dashes for separators
- Update bullet points from - to * in some contexts
- Improve version extraction regex with fallback logic
