refactor(i18n): split locale files into per-namespace modules (Phase K) (#688)

Each src/locales/<lang>.ts (~1800 LOC) becomes a folder src/locales/<lang>/
with one module per i18n namespace (44 each) plus an index.ts barrel that
reassembles <lang>Translation in the original key order.

Mechanical, script-driven split with a JSON round-trip check: every
locale object is byte-identical to its pre-split form. i18n.ts is
unchanged — './locales/<lang>' now resolves to the folder index.

The per-namespace settings.ts files land ~440-460 LOC; a single i18n
namespace is the natural, non-arbitrary split unit for a flat string
table, so they are intentionally left whole.

src/locales/zh/statistics.ts

@@ -0,0 +1,47 @@
+export const statistics = {
+  title: '统计',
+  recentlyPlayed: '最近播放',
+  mostPlayed: '最常播放的专辑',
+  highestRated: '评分最高的专辑',
+  genreDistribution: '流派分布（前 20）',
+  loadMore: '加载更多',
+  statArtists: '艺术家',
+  statArtistsTooltip: '仅限专辑艺术家——仅作为单曲艺术家出现（合唱、客串等）且无自己专辑的艺术家不计入此处。',
+  statAlbums: '专辑',
+  statSongs: '歌曲',
+  statGenres: '流派',
+  statPlaytime: '音频总时长',
+  genreInsights: '流派洞察',
+  formatDistribution: '格式分布',
+  formatSample: '{{n}} 首曲目的样本',
+  computing: '计算中…',
+  genreSongs: '{{count}} 首歌曲',
+  genreAlbums: '{{count}} 张专辑',
+  recentlyAdded: '最近添加',
+  decadeDistribution: '按年代分布的专辑',
+  decadeAlbums_one: '{{count}} 张专辑',
+  decadeAlbums_other: '{{count}} 张专辑',
+  decadeUnknown: '未知',
+  lfmTitle: 'Last.fm 统计',
+  lfmTopArtists: '热门艺术家',
+  lfmTopAlbums: '热门专辑',
+  lfmTopTracks: '热门曲目',
+  lfmPlays: '{{count}} 次播放',
+  lfmPeriodOverall: '全部时间',
+  lfmPeriod7day: '7 天',
+  lfmPeriod1month: '1 个月',
+  lfmPeriod3month: '3 个月',
+  lfmPeriod6month: '6 个月',
+  lfmPeriod12month: '12 个月',
+  lfmNotConnected: '在设置中连接 Last.fm 以查看您的统计。',
+  lfmRecentTracks: '最近记录',
+  lfmNowPlaying: '正在播放',
+  lfmJustNow: '刚刚',
+  lfmMinutesAgo: '{{n}} 分钟前',
+  lfmHoursAgo: '{{n}} 小时前',
+  lfmDaysAgo: '{{n}} 天前',
+  topRatedSongs: '最高评分歌曲',
+  topRatedArtists: '最高评分艺人',
+  noRatedSongs: '暂无已评分歌曲。请在专辑或播放列表中为歌曲评分。',
+  noRatedArtists: '暂无已评分艺人。',
+};