- scanner: replace serial DFS with 16-worker priority work-queue, one
scandir round trip per directory (DirEntry mtimes), per-subtree
exponential backoff (persisted in scan-state.json v2), leaf candidates
gated on max(dir, newest video file) mtime so growing downloads and
lazy NTFS dir mtimes are handled
- spec: collect_data_files('tracerite') so style.css/script.js ship
- guibuild: tolerate non-UTF-8 console when printing status glyphs
- ruff format pass on indexer.py/index_store.py (hook requirement)