665c315f56
Replace the [scanned, total] tuple progress event with a structured
{phase, processed, total, skipped} payload covering all three scan
phases (checking, hashing, confirming). find_duplicates now returns a
DuplicateScanResult with scanned/candidate/skipped counts, and the UI
surfaces phase labels plus a warning when unreadable files were
skipped. Also adds a clean:app script for cargo clean.