feat(settings): collapse Discord sub-options under one header

"Fetch covers from Apple Music" and "Custom text templates" are now both
tucked into a single collapsible "Advanced Discord options" block (default
collapsed) that only appears when Discord Rich Presence is enabled.
Reduces vertical noise in Settings → General for the common case where
users just flip Rich Presence on and leave the defaults.

Uses the same chevron-rotate pattern as the font picker and contributors
list. Adds `settings.discordOptions` key in all 8 locales.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/locales/nb.ts

@@ -537,6 +537,7 @@ export const nbTranslation = {
     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.',
+    discordOptions: 'Avanserte Discord-alternativer',
     discordTemplates: 'Egendefinerte tekstmaler',
     discordTemplatesDesc: 'Tilpass hvilken informasjon som vises på Discord-profilen din. Variabler: {title}, {artist}, {album}',
     discordTemplateDetails: 'Primær linje (details)',