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/zh.ts

@@ -153,6 +153,7 @@ export const zhTranslation = {
     trackDuration: '时长',
     trackTotal: '总计',
     columns: '列',
+    resetColumns: '重置为默认',
     notFound: '未找到专辑。',
     bioModal: '艺术家简介',
     bioClose: '关闭',
@@ -1084,6 +1085,10 @@ export const zhTranslation = {
     actionDelete: '从设备删除',
     actionApplyAll: '应用所有更改',
     templatePreview: '预览',
+    templatePresetStandard: '标准',
+    templatePresetMultiDisc: '多碟',
+    templatePresetAltFolder: '备用文件夹',
+    tokenSlashHint: '/ = 文件夹分隔符',
     cancel: '取消',
     noTargetDir: '请先选择目标文件夹。',
     noSources: '请至少选择一个来源。',