feat(albums): add 'Enqueue' option to album cover, context menu and multi-select toolbar (closes #253) (#256)

Per bcorporaal's request in #253: making a queue from multiple albums
required either replacing the queue (Play) or going into each album
detail page first. Three new entry points cover the common workflows:

1. Hover button on the album cover next to Play. Both buttons share
   the same accent style and size so the secondary action is just as
   readable as the primary — first attempt with a darker pill was hard
   to see and unbalanced the hover.

2. Context-menu entry "Enqueue Album" between "Open Album" and "Go to
   Artist". The i18n key already existed (was used by the album-song
   sub-context); just wiring up the action.

3. Multi-select toolbar in Albums.tsx: new "Enqueue (N)" button placed
   before "Add Offline" so power users selecting several albums no
   longer have to right-click. Plus a context-menu entry "Enqueue N
   Albums" for the same flow when a multi-album right-click happens
   anywhere else.

All multi-album fetches use Promise.all(getAlbum(...)) — Navidrome
handles parallel requests instantly (per memory note from PR #246).

i18n: 4 new keys per locale (3 with pluralisation: contextMenu.enqueueAlbums,
albums.enqueueSelected, albums.enqueueQueued).

Co-authored-by: Psychotoxical <dev@psysonic.app>
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/locales/zh.ts

@@ -99,6 +99,8 @@ export const zhTranslation = {
     playNext: '下一首播放',
     addToQueue: '添加到队列',
     enqueueAlbum: '专辑加入队列',
+    enqueueAlbums_one: '{{count}} 张专辑加入队列',
+    enqueueAlbums_other: '{{count}} 张专辑加入队列',
     startRadio: '开始电台',
     instantMix: '即时混音',
     instantMixFailed: '无法生成即时混音 — 服务器或插件出错。',
@@ -302,6 +304,10 @@ export const zhTranslation = {
     selectionCount: '{{count}} 已选择',
     downloadZips: '下载 ZIP',
     addOffline: '添加离线',
+    enqueueSelected_one: '加入队列 ({{count}})',
+    enqueueSelected_other: '加入队列 ({{count}})',
+    enqueueQueued_one: '已将 {{count}} 张专辑加入队列',
+    enqueueQueued_other: '已将 {{count}} 张专辑加入队列',
     downloadingZip: '正在下载 {{current}}/{{total}}: {{name}}',
     downloadZipDone: '已下载 {{count}} 个 ZIP',
     downloadZipFailed: '下载 {{name}} 失败',