111 of 122 top-level src/utils/ files move into 16 topic folders (audio,
cache, cover, share, server, playback, playlist, deviceSync, waveform,
mix, format, export, changelog, ui, perf, componentHelpers). True
singletons with no cluster stay at the utils/ root.
Pure file-move: a path-aware codemod rewrote 539 relative-import
specifiers across 275 files; no logic touched. The hot-path coverage
gate list (.github/frontend-hot-path-files.txt) is updated to the new
paths for the 11 gated utils files — a mechanical consequence of the
move, not a CI change. tsc is green.
Move the ~63-LOC `seek` action body into `runSeek(set, get, progress)`
in `src/store/seekAction.ts`, following the helper-with-thin-wrapper
pattern from E.37 (updateReplayGain).
The action handles the full seek path: 0..1 fraction → bounded time,
100 ms debounce, hot-cache-rebind branch via playTrack, and the
recoverable-seek-error retry burst (visual target pin + restart on
"not seekable" + bounded retry window).
Pure code-move. playerStore.ts: 938 → 868 LOC (−70).