feat(node,hub): add Videos group app (poster grid, flat list, TMDB metadata)

Implements docs/mediacenter.md: a "Videos" group application built on the
existing files index rather than a separate catalogue. On the node side,
new indexer enrichment (technical probe, filename/season parsing, thumbnail
generation) runs per-file once an operator has chosen a video_root for the
group, plus a TMDB client for on-demand poster/metadata lookups (never
client-side, thumbnails delivered over the existing chunk path). On the hub
side, a new video-app.js renders a lazily-mounted poster grid or a
thumbnail-only flat list, with TMDB entirely optional per group.

Along the way: the global apps registry now drives Settings' default-tab
picker instead of a hardcoded list, and the video_root is configured from
group Settings (like uploads) rather than from Files, with the node
refusing to run any TMDB/thumbnail work until one is set.

Fixes several bugs found via live testing against a real library, notably
a race between two effects writing the same "image ready" state that could
leave a poster grid spinning forever on a same-tab revisit — see
mediacenter.md §5.4 for the full account of each one.

1 files changed, 29 insertions, 0 deletions

diff --git a/packages/meshbay-hub/src/meshbay_hub/static/locales/zh-CN.js b/packages/meshbay-hub/src/meshbay_hub/static/locales/zh-CN.js
index ad8bf53..c9199c4 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/locales/zh-CN.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/locales/zh-CN.js
@@ -73,6 +73,7 @@ export default {
   'group.default_name': '群组',
   'group.tab_files': '文件',
   'group.tab_chat': '聊天',
+  'group.tab_video': '视频',
   'group.tab_members': '成员',
   'group.tab_settings': "设置",
   'members.danger_leave_hint': "您将无法再访问该群组的文件和聊天。",
@@ -149,6 +150,18 @@ export default {
   'group.upload_indexing': '建立索引中…',
   'video.err_transport': '传输未连接',
   'video.err_mse': '该编解码器不支持流式播放：{codec}',
+  'video.mode_poster': '海报视图',
+  'video.mode_flat': '平铺列表',
+  'video.empty': '未找到视频。',
+  'video.no_root_configured': '此群组尚未设置视频根目录 — 操作员可以在设置中选择一个。',
+  'video.director': '导演',
+  'video.specials': '特别篇',
+  'video.season_n': '第 {n} 季',
+  'video.episode_n': '第 {n} 集',
+  'video.n_episodes': {
+    one: '{n} 集',
+    other: '{n} 集',
+  },
 
   // LAN cast
   'cast.start': '投射到设备',
@@ -551,6 +564,22 @@ export default {
   'settings_node.scan_save': '保存',
   'settings_node.scan_saving': '保存中…',
   'settings_node.scan_saved': '已保存。',
+  'settings_node.tmdb_title': 'TMDB 元数据',
+  'settings_node.tmdb_hint': '允许视频应用显示来自 TMDB 的海报、简介和演职人员。关闭后仅显示缩略图浏览，不会向第三方发送任何请求。',
+  'settings_node.tmdb_enabled': '已启用',
+  'settings_node.tmdb_disabled': '已禁用',
+  'settings_node.tmdb_token_label': '自定义 API 令牌（可选）',
+  'settings_node.tmdb_token_placeholder': '留空以使用内置的默认令牌',
+  'settings_node.tmdb_token_customized': '已设置自定义令牌。',
+  'settings_node.tmdb_token_default': '正在使用内置的默认令牌。',
+  'settings_node.tmdb_save': '保存',
+  'settings_node.tmdb_language_label': '语言',
+  'settings_node.tmdb_language_hint': '适用于所有人 — 共享同一个缓存，不是按观看者分别请求。',
+  'settings_node.video_root_title': '视频根目录',
+  'settings_node.video_root_hint': '该文件夹（或子文件夹）将作为此群组"视频"应用的入口。在选择之前，"视频"中不会显示任何内容，也不会执行任何 TMDB 查询。',
+  'settings_node.video_root_none': '— 未选择 —',
+  'settings_node.video_root_save': '保存',
+  'settings_node.video_root_change_confirm': '更改视频根目录会替换每位成员在"视频"标签页中看到的内容。是否继续？',
 
   // Create group wizard
   'wizard.title': '创建群组',