fix(audio): stabilize loudness normalization and streaming startup behavior

Improve normalization consistency by separating cache refresh for non-playing tracks, hardening track-id cache lookups, and keeping UI gain state aligned with actual playback. Also reduce startup stalls by preferring non-seekable streaming when format hints are missing and by tuning ALSA/analysis paths to avoid underrun-prone churn.

src/store/analysisSync.ts

@@ -0,0 +1,29 @@
+export type AnalysisStorageChangedReason =
+  | 'offline-delete'
+  | 'hotcache-delete'
+  | 'hotcache-purge';
+
+export type AnalysisStorageChangedDetail = {
+  trackId?: string | null;
+  reason: AnalysisStorageChangedReason;
+};
+
+const EVENT_NAME = 'psysonic:analysis-storage-changed';
+
+export function emitAnalysisStorageChanged(detail: AnalysisStorageChangedDetail): void {
+  if (typeof window === 'undefined') return;
+  window.dispatchEvent(new CustomEvent<AnalysisStorageChangedDetail>(EVENT_NAME, { detail }));
+}
+
+export function onAnalysisStorageChanged(
+  listener: (detail: AnalysisStorageChangedDetail) => void,
+): () => void {
+  if (typeof window === 'undefined') return () => {};
+  const wrapped = (evt: Event) => {
+    const ce = evt as CustomEvent<AnalysisStorageChangedDetail>;
+    if (!ce?.detail) return;
+    listener(ce.detail);
+  };
+  window.addEventListener(EVENT_NAME, wrapped as EventListener);
+  return () => window.removeEventListener(EVENT_NAME, wrapped as EventListener);
+}