feat: romaji override list — manual kanji→romaji corrections for sort tags

Adds a maintained list in Settings where you can map kanji artist/album/title
strings to their correct romaji reading (e.g. 照井順政 → Terui Yoshimasa).
Overrides are applied last (highest priority) when the edit-metadata modal
opens, so saving the song writes the correct sort tags permanently to the file.

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

index.html

@@ -657,6 +657,20 @@
           <div id="s-show-romaji" class="toggle" onclick="this.classList.toggle('on')"></div>
         </div>
       </div>
+      <div class="settings-section">
+        <h3 style="display:flex;align-items:center;gap:8px;margin-bottom:6px">
+          <span style="width:24px;height:24px;border-radius:6px;background:var(--accent-dim);display:inline-flex;align-items:center;justify-content:center;font-size:12px">㊙</span>
+          Romaji Korrekturen
+        </h3>
+        <div class="hint" style="margin-bottom:10px">Kanji → korrektes Romaji. Wird in Sort-Tags automatisch übernommen.</div>
+        <div id="romaji-overrides-list" style="display:flex;flex-direction:column;gap:5px;margin-bottom:10px"></div>
+        <div style="display:flex;gap:6px;align-items:center">
+          <input id="ro-kanji"  placeholder="照井順政" style="flex:1;padding:8px 10px;background:var(--bg2);border:1px solid var(--border2);border-radius:8px;color:var(--text);font-family:var(--font);font-size:13px;outline:none" onkeydown="if(event.key==='Enter')addRomajiOverrideUI()">
+          <span style="color:var(--text2);flex-shrink:0">→</span>
+          <input id="ro-romaji" placeholder="Terui Yoshimasa" style="flex:1.2;padding:8px 10px;background:var(--bg2);border:1px solid var(--border2);border-radius:8px;color:var(--text);font-family:var(--font);font-size:13px;outline:none" onkeydown="if(event.key==='Enter')addRomajiOverrideUI()">
+          <button onclick="addRomajiOverrideUI()" style="flex-shrink:0;padding:8px 12px;border-radius:8px;border:none;background:linear-gradient(135deg,var(--accent),var(--accent-dark));color:#000;font-family:var(--font);font-size:14px;font-weight:700;cursor:pointer">+</button>
+        </div>
+      </div>
       <div class="settings-section">
         <h3 style="display:flex;align-items:center;gap:8px;margin-bottom:12px">
           <span style="width:24px;height:24px;border-radius:6px;background:var(--surface2);display:inline-flex;align-items:center;justify-content:center;font-size:12px">🎨</span>