scoring: reject aliases between generated CSV destinations #114

If checks.csv is a symlink or hardlink to measurements.csv inside the output directory, the second write replaces the first generated report. Source inputs remain protected. A clean output directory recovers all reports. Compare the three output paths by resolved path and file identity before writing; test both link forms.

Confirmed at a575437 from PR #4 discussion_r4114179701. Deferred under the approved convergence rule: no source-input loss or false PASS was found.