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/sidebar/SidebarNavBody.tsx

@@ -5,7 +5,7 @@ import { AudioLines, ChevronRight, HardDriveDownload, PlayCircle, Settings, Spar
 import type { SidebarItemConfig } from '../../store/sidebarStore';
 import { ALL_NAV_ITEMS } from '../../config/navItems';
 import WhatsNewBanner from '../WhatsNewBanner';
-import { displayPlaylistName, isSmartPlaylistName } from '../../utils/sidebarHelpers';
+import { displayPlaylistName, isSmartPlaylistName } from '../../utils/componentHelpers/sidebarHelpers';
 import SidebarLibraryPicker from './SidebarLibraryPicker';
 import SidebarActiveJobs from './SidebarActiveJobs';
 

src/components/sidebar/SidebarPerfProbeModal.tsx

@@ -1,7 +1,7 @@
 import { createPortal } from 'react-dom';
 import { X } from 'lucide-react';
 import SidebarPerfProbePhase2 from './SidebarPerfProbePhase2';
-import { resetPerfProbeFlags, setPerfProbeFlag, type PerfProbeFlags } from '../../utils/perfFlags';
+import { resetPerfProbeFlags, setPerfProbeFlag, type PerfProbeFlags } from '../../utils/perf/perfFlags';
 
 interface PerfCpu {
   app: number;

src/components/sidebar/SidebarPerfProbePhase2.tsx

@@ -1,4 +1,4 @@
-import { setPerfProbeFlag, type PerfProbeFlags } from '../../utils/perfFlags';
+import { setPerfProbeFlag, type PerfProbeFlags } from '../../utils/perf/perfFlags';
 
 export default function SidebarPerfProbePhase2({ perfFlags }: { perfFlags: PerfProbeFlags }) {
   return (