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/en.js b/packages/meshbay-hub/src/meshbay_hub/static/locales/en.js
index 8c5cbe5..d1aca93 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/locales/en.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/locales/en.js
@@ -634,6 +634,8 @@ export default {
   'settings_app.tmdb_token_prompt': 'Sign up on TMDB to generate your own API key.',
   'settings_app.tmdb_token_link': 'Get a key',
   'settings_node.roots_offline_hint': 'Not connected to the node — changes go through the local node instead, and take effect on its next reload.',
+  'settings_node.roots_node_too_old': 'This node is older than this page: it can show its directories but not change them here. Update it, or use the meshbay-node root commands.',
+  'settings_node.app_node_too_old': 'This node is older than this page and has no setting for this app yet. Update it to configure this here.',
   'settings_node.directories_title': 'App directories',
   'settings_node.directories_hint': 'Which shared folders the Videos, Music and Photos apps use as their entry point(s).',