fix: iTunes Japanese artist lookup + sort tag editing in info modal

- views.js: skip ASCII word-match when artist name is non-ASCII so Japanese
  artists (e.g. ヨルシカ) resolve correctly to an iTunes artist ID
- index.html + styles.css: collapsible Sort-Tags section in edit modal
- ui.js: pre-fill sort fields from romaji index; include in save body
- novasonic-server.js: accept manual titleSort/artistSort/albumArtistSort/albumSort
  overrides; fall back to auto-computed romaji when not provided

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

styles.css

@@ -485,6 +485,7 @@ button:focus{outline:none}
 .info-edit-art-btn{font-size:11px;color:var(--text2);background:var(--surface2);border:none;border-radius:6px;padding:4px 8px;cursor:pointer;display:flex;align-items:center;gap:4px;font-family:var(--font)}
 .info-edit-art-btn:hover{color:var(--text)}
 .info-edit-fields{display:flex;flex-direction:column;gap:8px;padding:0 20px 4px}
+.ie-sort-details{padding:0 20px 4px;font-size:11px;color:var(--text3)}.ie-sort-details summary{cursor:pointer;font-weight:500;color:var(--text2);padding:4px 0;list-style:none;display:flex;align-items:center;gap:6px;user-select:none}.ie-sort-details summary::before{content:'▶';font-size:9px;transition:transform .15s}.ie-sort-details[open] summary::before{transform:rotate(90deg)}.ie-sort-details .info-edit-fields{padding:0}
 .info-edit-label{display:flex;flex-direction:column;font-size:11px;color:var(--text3);gap:3px;font-weight:500}
 .info-edit-hint{font-size:10px;color:var(--text3);font-weight:400;opacity:.7;margin-top:-1px}
 .info-edit-hint code{background:var(--surface3,var(--surface2));border-radius:3px;padding:0 3px;font-size:10px;font-family:monospace;opacity:.9}