feat: romaji search for Japanese songs via wanakana

When search input is pure ASCII (romaji), converts it to hiragana in
parallel using wanakana and merges both result sets. Deduplicates by ID
so no double entries. Helps find artists/songs tagged with hiragana in
sort fields (e.g. 'inabakumori' → 'いなばくもり').

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/views.js

@@ -692,6 +692,24 @@ export async function loadRandom() {
   } catch(e) { el.innerHTML = `<p style="color:var(--danger)">${e.message}</p>`; }
 }
 
+// ─── ROMAJI → HIRAGANA (lazy-loaded) ───
+let _wanakana = null;
+async function _romajiToHiragana(q) {
+  // Only attempt conversion if query is pure ASCII (likely romaji)
+  if (!/^[a-z\s'-]+$/i.test(q.trim())) return null;
+  try {
+    if (!_wanakana) _wanakana = await import('https://cdn.jsdelivr.net/npm/wanakana@5/esm/wanakana.js');
+    const h = _wanakana.toHiragana(q.trim(), { passRomaji: false });
+    // If conversion produced actual hiragana (not just the same ASCII), use it
+    return /[぀-ゟ]/.test(h) ? h : null;
+  } catch { return null; }
+}
+
+function _mergeUniq(a, b) {
+  const seen = new Set(a.map(x => x.id));
+  return [...a, ...(b || []).filter(x => !seen.has(x.id))];
+}
+
 // ─── LOCAL SEARCH ───
 export function onLocalSearch(val) {
   clearTimeout(S.searchTimer);
@@ -704,10 +722,17 @@ export async function doLocalSearch(q) {
   const el = document.getElementById('search-results');
   el.innerHTML = '<div class="spinner"></div>';
   try {
-    const r = await api('search3', `&query=${encodeURIComponent(q)}&songCount=30&albumCount=10&artistCount=6`);
+    const hiragana = await _romajiToHiragana(q);
-    const res = r.searchResult3 || {};
+    const [r, r2] = await Promise.all([
+      api('search3', `&query=${encodeURIComponent(q)}&songCount=30&albumCount=10&artistCount=6`),
+      hiragana ? api('search3', `&query=${encodeURIComponent(hiragana)}&songCount=20&albumCount=6&artistCount=4`) : Promise.resolve(null),
+    ]);
+    const res  = r.searchResult3  || {};
+    const res2 = r2?.searchResult3 || {};
     el.innerHTML = '';
-    const artists = res.artist||[], albums = res.album||[], songs = res.song||[];
+    const artists = _mergeUniq(res.artist||[], res2.artist);
+    const albums  = _mergeUniq(res.album ||[], res2.album);
+    const songs   = _mergeUniq(res.song  ||[], res2.song);
     if(!artists.length && !albums.length && !songs.length) {
       el.innerHTML = '<div class="empty-state"><div class="icon">🔍</div><p>Keine Ergebnisse</p></div>'; return;
     }