fix: auto-populate artist sort map on album page — no Artists page visit needed

ensureArtistSortMap() fetches getArtists once per session (cached) and
populates _artistSortMap automatically. Called at start of loadAlbumDetail
when showRomaji is on, so artist sort names are always available.

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

src/views/detail.js

@@ -1,6 +1,6 @@
 import { S } from '../state.js';
 import { esc, toast } from '../utils.js';
-import { api, coverUrl, itunesSearch, itunesLookupAlbum, itunesLookupArtistSongs, itunesLookupArtistAlbums, fetchRomajiIndex, dispArtistById, dispAlbumName, cacheArtistSortNames } from '../api.js';
+import { api, coverUrl, itunesSearch, itunesLookupAlbum, itunesLookupArtistSongs, itunesLookupArtistAlbums, fetchRomajiIndex, dispArtistById, dispAlbumName, cacheArtistSortNames, ensureArtistSortMap } from '../api.js';
 import { makeCard, makeAlbumCard, makeGlobalTrackItem, makeSongItem } from '../ui/components.js';
 import { playQueue, dlSongLocal, toggleStar, parseArtists } from '../player/player.js';
 import { showCtxMenu, openDlModal } from '../ui/ui.js';
@@ -378,6 +378,7 @@ export async function loadItunesAlbumDetail(album) {
 
 // ─── ALBUM DETAIL ───
 export async function loadAlbumDetail(album) {
+  if (S.cfg.showRomaji) await ensureArtistSortMap().catch(() => {});
   document.getElementById('album-back-btn').onclick = () =>
     album._fromArtist ? navigate('artist-detail', album._fromArtist) : navigate('albums');
   document.getElementById('album-detail-name').textContent = dispAlbumName(album);