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/utils/componentHelpers/miniPlayerHelpers.ts

@@ -0,0 +1,82 @@
+import { usePlayerStore } from '../../store/playerStore';
+import type { MiniSyncPayload, MiniTrackInfo } from '../miniPlayerBridge';
+
+export const COLLAPSED_SIZE = { w: 340, h: 260 };
+export const EXPANDED_SIZE  = { w: 340, h: 500 };
+// Minimum window dimensions per state. When the queue is open the floor must
+// keep at least two queue rows visible; a stricter min would let the user
+// collapse the queue area to nothing while it's still toggled on.
+export const COLLAPSED_MIN  = { w: 320, h: 240 };
+export const EXPANDED_MIN   = { w: 320, h: 340 };
+
+// Persist the expanded-window height so reopening the queue restores the
+// user's preferred size instead of snapping back to EXPANDED_SIZE.h.
+export const EXPANDED_H_KEY = 'psysonic_mini_expanded_h';
+export function readStoredExpandedHeight(): number {
+  try {
+    const raw = localStorage.getItem(EXPANDED_H_KEY);
+    if (raw) {
+      const n = parseInt(raw, 10);
+      if (Number.isFinite(n) && n >= EXPANDED_MIN.h) return n;
+    }
+  } catch {}
+  return EXPANDED_SIZE.h;
+}
+
+// Persist whether the queue panel was open so the next launch restores
+// the same state. Same scope as the height: localStorage of the mini
+// webview (shared across mini sessions, separate from the main store).
+export const QUEUE_OPEN_KEY = 'psysonic_mini_queue_open';
+export function readQueueOpen(): boolean {
+  try { return localStorage.getItem(QUEUE_OPEN_KEY) === '1'; } catch { return false; }
+}
+
+export function toMini(t: any): MiniTrackInfo {
+  return {
+    id: t.id,
+    title: t.title,
+    artist: t.artist,
+    album: t.album,
+    albumId: t.albumId,
+    artistId: t.artistId,
+    coverArt: t.coverArt,
+    duration: t.duration,
+    starred: !!t.starred,
+    year: t.year,
+  };
+}
+
+/**
+ * Hydrate from the persisted playerStore so initial paint shows real content
+ * instead of "—" while we wait for the mini:sync event from the main window.
+ * The persisted state covers the cold-start window (webview boot + bundle).
+ */
+export function initialSnapshot(): MiniSyncPayload {
+  try {
+    const s = usePlayerStore.getState();
+    return {
+      track: s.currentTrack ? toMini(s.currentTrack) : null,
+      queue: (s.queue ?? []).map(toMini),
+      queueIndex: s.queueIndex ?? 0,
+      isPlaying: s.isPlaying,
+      volume: s.volume ?? 1,
+      gaplessEnabled: false,
+      crossfadeEnabled: false,
+      infiniteQueueEnabled: false,
+      isMobile: false,
+    };
+  } catch {
+    return {
+      track: null, queue: [], queueIndex: 0, isPlaying: false,
+      volume: 1, gaplessEnabled: false, crossfadeEnabled: false,
+      infiniteQueueEnabled: false, isMobile: false,
+    };
+  }
+}
+
+export function fmt(seconds: number): string {
+  if (!isFinite(seconds) || seconds < 0) seconds = 0;
+  const m = Math.floor(seconds / 60);
+  const s = Math.floor(seconds % 60);
+  return `${m}:${s.toString().padStart(2, '0')}`;
+}