i18n(settings): translate Cover art cache section into the remaining locales (#1047)

The Cover art cache settings section shipped with English (and Russian)
strings only. Add the 23 keys (scope/strategy labels, Lazy/Aggressive
descriptions, per-server clear dialog) for de, fr, es, nl, nb, ro, and zh.
Placeholders and the technical progress-value string are left verbatim.

src/locales/zh/settings.ts

@@ -154,6 +154,29 @@ export const settings = {
   cacheUsedHot: '占用空间：',
   hotCacheTrackCount: '缓存曲目数：',
   cacheMaxLabel: '最大容量',
+  imageCacheScopeLabel: '范围',
+  imageCacheSubTitle: '浏览器内预览',
+  coverDiskCacheSubTitle: '磁盘封面缓存',
+  coverCacheStrategyTitle: '封面缓存',
+  coverCacheStrategyDesc: '你可以为每台服务器选择一种策略：懒加载——按需加载封面；激进——按需加载并额外在后台预加载。',
+  coverCacheStrategyLabel: '策略',
+  coverCacheStrategyServerLabel: '服务器',
+  coverCacheStrategyProgressLabel: '缓存',
+  coverCacheStrategyActionsLabel: '操作',
+  coverCacheStrategyLazy: '懒加载',
+  coverCacheStrategyLazyDesc: '仅在需要时加载封面。',
+  coverCacheStrategyAggressive: '激进',
+  coverCacheStrategyAggressiveDesc: '懒加载行为，并额外在后台预加载。',
+  coverCacheStrategyDiskUsage: '磁盘占用：{{size}}',
+  coverCacheStrategyProgressValue: '{{percent}}% ({{done}}/{{total}}) · {{size}}',
+  coverCacheStrategyClearAction: '清除封面缓存',
+  coverCacheStrategyClearTitle: '清除封面缓存？',
+  coverCacheStrategyClearDesc: '移除 {{server}} 的所有已缓存封面图片。需要时会重新下载。',
+  coverCacheStrategyClearConfirm: '清除',
+  coverCacheStrategyClearCancel: '取消',
+  coverCacheStrategyClearSuccess: '已清除此服务器的封面缓存。',
+  coverCacheStrategyClearError: '清除封面缓存失败。',
+  coverCacheStrategyServerRemoved: '已移除的服务器',
   cacheClearBtn: '清除缓存',
   cacheClearWarning: '将清除所有已缓存的封面和艺术家图片，需要时会重新下载。',
   cacheClearConfirm: '清除图片缓存',