feat: server-side romaji overrides (shared list); preload ExoPlayer from SharedPreferences on cold start

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

src/ui.js

@@ -92,7 +92,7 @@ export async function addRomajiOverrideUI() {
   const k = (document.getElementById('ro-kanji')?.value  || '').trim();
   const v = (document.getElementById('ro-romaji')?.value || '').trim();
   if (!k || !v) { toast('⚠ Kanji und Romaji eingeben'); return; }
-  setRomajiOverride(k, v);
+  await setRomajiOverride(k, v);
   document.getElementById('ro-kanji').value  = '';
   document.getElementById('ro-romaji').value = '';
   _renderRomajiOverrides();
@@ -111,8 +111,8 @@ export async function addRomajiOverrideUI() {
     toast('⚠ Fix-Artist-Sort: ' + e.message);
   }
 }
-export function removeRomajiOverrideUI(kanji) {
-  removeRomajiOverride(kanji);
+export async function removeRomajiOverrideUI(kanji) {
+  await removeRomajiOverride(kanji);
   _renderRomajiOverrides();
 }
 export function openRomajiOverridesModal() {