feat: normalize Japanese artist/title names to romaji at storage time

- Add romajiForStorage() to romaji.js — smart word spacing + Title Case
- ytdlp.js: apply to folder names, filenames, and embedded tags
- novasonic-server.js: apply in edit-metadata endpoint and Spotify resolve
- spotify.js: update track artist/name from iTunes canonical English names

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

src/spotify.js

@@ -295,6 +295,10 @@ async function _loadSpotifyTrackArtwork(tracks, listEl) {
         if (match.trackExplicitness)  t.trackExplicitness  = match.trackExplicitness;
         if (match.previewUrl)         t.previewUrl         = match.previewUrl;
         if (match.trackTimeMillis)    t.durationMs         = match.trackTimeMillis;
+        // Use iTunes canonical English/romaji names — more accurate than Spotify (which may use Japanese)
+        if (match.artistName)         t.artistName         = match.artistName;
+        const JP_RE = /[぀-ヿ一-鿿]/;
+        if (JP_RE.test(t.trackName) && match.trackName) t.trackName = match.trackName;
         if (window._spotifyResolved?.tracks?.[idx]) Object.assign(window._spotifyResolved.tracks[idx], t);
         const url = match.artworkUrl100 || match.artworkUrl60 || '';
         if (url) _setArt(artEls[idx], url);