refactor(utils): group utils/ files into topic folders (Phase L, part 1) (#689)

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.

src/components/albumTrackList/AlbumTrackListMobile.tsx

@@ -2,8 +2,8 @@ import React from 'react';
 import { AudioLines } from 'lucide-react';
 import type { SubsonicSong } from '../../api/subsonicTypes';
 import type { Track } from '../../store/playerStoreTypes';
-import { songToTrack } from '../../utils/songToTrack';
-import { formatDuration } from '../../utils/albumTrackListHelpers';
+import { songToTrack } from '../../utils/playback/songToTrack';
+import { formatDuration } from '../../utils/componentHelpers/albumTrackListHelpers';
 
 interface Props {
   discNums: number[];

src/components/albumTrackList/TrackRow.tsx

@@ -5,12 +5,12 @@ import { useNavigate } from 'react-router-dom';
 import type { ColDef } from '../../utils/useTracklistColumns';
 import type { SubsonicSong } from '../../api/subsonicTypes';
 import type { Track } from '../../store/playerStoreTypes';
-import { songToTrack } from '../../utils/songToTrack';
+import { songToTrack } from '../../utils/playback/songToTrack';
 import { useSelectionStore } from '../../store/selectionStore';
 import { useThemeStore } from '../../store/themeStore';
 import { usePreviewStore } from '../../store/previewStore';
 import StarRating from '../StarRating';
-import { codecLabel, formatDuration, type ColKey } from '../../utils/albumTrackListHelpers';
+import { codecLabel, formatDuration, type ColKey } from '../../utils/componentHelpers/albumTrackListHelpers';
 
 type ContextMenuFn = (
   x: number,

src/components/albumTrackList/TracklistColumnPicker.tsx

@@ -1,7 +1,7 @@
 import React from 'react';
 import { Check, ChevronDown, RotateCcw } from 'lucide-react';
 import type { TFunction } from 'i18next';
-import { COLUMNS } from '../../utils/albumTrackListHelpers';
+import { COLUMNS } from '../../utils/componentHelpers/albumTrackListHelpers';
 
 interface Props {
   pickerRef: React.RefObject<HTMLDivElement | null>;

src/components/albumTrackList/TracklistHeaderRow.tsx

@@ -1,7 +1,7 @@
 import React from 'react';
 import type { TFunction } from 'i18next';
 import type { ColDef } from '../../utils/useTracklistColumns';
-import { CENTERED_COLS, isSortable, type ColKey, type SortKey } from '../../utils/albumTrackListHelpers';
+import { CENTERED_COLS, isSortable, type ColKey, type SortKey } from '../../utils/componentHelpers/albumTrackListHelpers';
 
 interface Props {
   visibleCols: readonly ColDef[];