feat: tracklist column reset, device sync cross-platform template fix, filename template builder, privacy policy

- Add "Reset to defaults" button to column picker in AlbumTrackList, PlaylistDetail, Favorites (all 8 locales)
- Fix device sync cross-OS status detection: store filenameTemplate in manifest, use it for path computation on import
- Redesign filename template UI: preset buttons (Standard/Multi-Disc/Alt. Folder), clickable token chips ({artist}, {album}, etc.), clear button
- Fix suggestions section in PlaylistDetail missing album column rendering
- Add PRIVACY.md documenting all third-party integrations (Last.fm, LRCLIB, Apple Music, Discord); link from README

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

src/locales/fr.ts

@@ -154,6 +154,7 @@ export const frTranslation = {
     trackDuration: 'Durée',
     trackTotal: 'Total',
     columns: 'Colonnes',
+    resetColumns: 'Réinitialiser',
     notFound: 'Album introuvable.',
     bioModal: 'Biographie de l\'artiste',
     bioClose: 'Fermer',
@@ -1091,6 +1092,10 @@ export const frTranslation = {
     actionDelete: 'Supprimer de l\'appareil',
     actionApplyAll: 'Appliquer toutes les modifications',
     templatePreview: 'Aperçu',
+    templatePresetStandard: 'Standard',
+    templatePresetMultiDisc: 'Multi-Disc',
+    templatePresetAltFolder: 'Dossier alt.',
+    tokenSlashHint: '/ = séparateur de dossier',
     cancel: 'Annuler',
     noTargetDir: 'Veuillez d\'abord choisir un dossier cible.',
     noSources: 'Veuillez sélectionner au moins une source.',