fix(client): degrade against a node still speaking MNP 1.0

The SPA is served by the hub, so deploying the hub puts this client in front of
every node — including the ones not updated yet. That window is the normal
state for as long as an operator takes, and for a node someone else runs it may
be indefinite. Three controls were broken across it, and the failure mode is
quiet: an unknown message type is logged by the node and never answered, so the
click produces a thirty-second wait ending in a timeout with nothing on screen
to say the node simply cannot do this.

Files' Upload button read `root.writable`, which a 1.0 node does not send — it
says `upload`, the same answer under the older name. The button disappeared on
every un-upgraded node. It reads both now, and still respects an explicit
`writable: false` rather than falling through to the legacy flag.

The per-app folder pickers spoke `app_directories`. Videos, Music and Photos
each had their own message before that and those still work, so the page
chooses by version: an operator on an older node keeps the ability they had.
`video_root` and `audio_root` hold one folder, so several are refused with a
reason rather than stored as the first and silently truncated.

Root management — writable, removable, eject, plug — has no older equivalent to
route to, so the table goes read-only with a line saying why and pointing at
the `meshbay-node root` commands. Chat's two settings are new with nothing
before them and are hidden the same way.

None of this was inferred from a payload's shape: `_checkNodeVersion` already
parsed the node's version and threw it away, and it is kept now. Coupling a
capability to whether some field happens to be present is how a flag flips
because an unrelated payload changed.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011pvMdvLBG92jyhvD5pD6us

1 files changed, 2 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 e0886a2..68d794e 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
@@ -827,6 +827,8 @@ export default {
   'settings_app.tmdb_token_prompt': '在 TMDB 注册以生成你自己的 API 密钥。',
   'settings_app.tmdb_token_link': '获取密钥',
   'settings_node.roots_offline_hint': '未连接到节点 — 变更将通过本地节点进行，并在其下次重新加载时生效。',
+  'settings_node.roots_node_too_old': '该节点比本页面旧：它能显示自己的目录，但无法在此更改。请更新节点，或使用 meshbay-node root 命令。',
+  'settings_node.app_node_too_old': '该节点比本页面旧，尚不支持此应用的设置。请更新节点后在此配置。',
   'settings_node.directories_title': '应用目录',
   'settings_node.directories_hint': '共享文件夹，以及“视频”“音乐”和“照片”应用各自使用哪个（些）作为入口。',