feat(discord): add server cover art source (#462)

* feat(discord): add server cover art source

The old Apple Music toggle is replaced with a radio selector which let's you choose
between Apple Music, Server and no image.

It's important to note that the server needs to be publicly accessible.

Translations have been added for all locales

* feat(discord): toggle UI for cover source and tightened defaults

- Replace cover-source radio buttons with three indented sub-toggles
  (none / server / apple) under Discord Rich Presence; mutex via
  setDiscordCoverSource — turning one on flips the others off.
- Default discordCoverSource is now 'server' for fresh installs
  (opt-in friendly: own server, no third-party data leak). Existing
  users keep their state via the legacy bool migration.
- Tighten template defaults: details {artist}, state {title}, largeText
  unchanged. Existing users keep their persisted values.

* docs(contributors): credit Sayykii + changelog entry for #462

---------

Co-authored-by: Psychotoxical <171614930+Psychotoxical@users.noreply.github.com>

src/locales/nb.ts

@@ -696,8 +696,11 @@ export const nbTranslation = {
     linuxWebkitSmoothScrollDesc: 'På: treg rull med etterslep. Av: trinnvis som i GTK.',
     discordRichPresence: 'Discord Rich Presence',
     discordRichPresenceDesc: 'Vis sporet som spilles i din Discord-profil. Krever at Discord kjører.',
-    discordAppleCovers: 'Hent covere fra Apple Music til Discord',
-    discordAppleCoversDesc: 'Sender artist- og albumnavn til Apples søke-API for å finne cover til Discord-profilen din. Deaktivert som standard av personvernhensyn.',
+    discordCoverSource: 'Coverkilde',
+    discordCoverSourceDesc: 'Hvor albumcoveret for Discord-profilen din hentes fra.',
+    discordCoverNone: 'Ingen (kun app-ikon)',
+    discordCoverServer: 'Server (via albuminfo)',
+    discordCoverApple: 'Apple Music',
     discordOptions: 'Avanserte Discord-alternativer',
     discordTemplates: 'Egendefinerte tekstmaler',
     discordTemplatesDesc: 'Tilpass hvilken informasjon som vises på Discord-profilen din. Variabler: {title}, {artist}, {album}',