fix(artist-detail): Last.fm/Wikipedia/Favorite hover keeps button border (#966)

* fix(artist-detail): keep ext-link border visible on hover

Hover used --border-subtle, which on Catppuccin matches --bg-card and
visually erased the rim while only the fill changed. Match btn-surface:
--ctp-surface1 border, --ctp-overlay0 on hover.

* docs(changelog): credit zunoz on Psysonic Discord for PR #966

* fix(playlists): tooltips on Play/Add Songs and song count pluralization

Add data-tooltip to Play and Add Songs in playlist hero; switch
playlists.songs to count-based _one/_other forms (was {{n}} without
i18next plural suffix, breaking spacing and singular).

* fix(playlists): render BPM and optional cols in Suggested Songs rows

PlaylistSuggestions shared column headers with the main tracklist but
its row switch omitted bpm, genre, playCount, and lastPlayed.

src/locales/de/playlists.ts

@@ -9,8 +9,10 @@ export const playlists = {
   emptyPlaylist: 'Diese Playlist ist leer.',
   addFirstSong: 'Ersten Song hinzufügen',
   notFound: 'Playlist nicht gefunden.',
-  songs: '{{n}} Songs',
+  songs_one: '{{count}} Song',
+  songs_other: '{{count}} Songs',
   playAll: 'Alle abspielen',
+  playTooltip: 'Playlist abspielen',
   shuffle: 'Zufallswiedergabe',
   addToQueue: 'Zur Warteschlange',
   back: 'Zurück zu Playlists',
@@ -18,6 +20,7 @@ export const playlists = {
   confirmDelete: 'Nochmals klicken zum Bestätigen',
   removeSong: 'Aus Playlist entfernen',
   addSongs: 'Songs hinzufügen',
+  addSongsTooltip: 'Bibliothek durchsuchen und Titel hinzufügen',
   searchPlaceholder: 'Bibliothek durchsuchen…',
   noResults: 'Keine Ergebnisse.',
   suggestions: 'Vorgeschlagene Songs',