Performance improvements:
- Load all known files from DB into memory at startup
- Check file changes against in-memory map (no per-file DB queries)
- Batch database writes in groups of 1000 files per transaction
- Scan phase now only counts regular files, not directories
This should improve scan speed from ~600 files/sec to potentially
10,000+ files/sec by eliminating per-file database round trips.
sneak
c3725e745e