[Bug] Wrong unreferenced files metrics

[kimfrie]

Bug: All files incorrectly reported as unreferenced

Problem

unreferenced_files contains ALL data files instead of only orphaned files.

Root Cause

Path format mismatch in delta_lake.rs ~line 55:

• Delta log stores relative paths: partition_key=2026-01-01/part-xxx.parquet
• Comparison uses full S3 keys: some/s3/prefix/partition_key=2026-01-01/part-xxx.parquet

HashSet::contains() requires exact equality, so these never match.

Fix

Normalize paths before comparison - strip prefix from S3 key OR prepend prefix to Delta log paths.

[kimfrie]

to add: As far as I understand this also skews the health score in the end