fix: iTunes JP-first with US fallback; romaji filter in playlist/starred search

src/api.js

@@ -135,10 +135,12 @@ function _itunesBase() {
 
 export async function itunesSearch(query, entity='musicTrack', limit=25) {
   try {
-    const r = await fetch(`${_itunesBase()}/search?term=${encodeURIComponent(query)}&media=music&entity=${entity}&limit=${limit}&country=jp&explicit=Yes`);
-    const text = await r.text();
-    if (!text) return [];
-    return JSON.parse(text).results || [];
+    const base = `${_itunesBase()}/search?term=${encodeURIComponent(query)}&media=music&entity=${entity}&limit=${limit}&explicit=Yes`;
+    const rJp = await fetch(`${base}&country=jp`);
+    const jpResults = JSON.parse(await rJp.text()).results || [];
+    if (jpResults.length) return jpResults;
+    const rUs = await fetch(`${base}&country=us`);
+    return JSON.parse(await rUs.text()).results || [];
   } catch { return []; }
 }