feat(client): Phase 2 — per-app settings panes, folder tree, multi-directory

Each app's settings were inlined in `group-settings.js` — TMDB, MusicBrainz,
and one folder picker per app, each with its own draft state and save handler
saying the same thing about a different key. They are one file per app now,
reached through the `apps.js` registry, and the page that renders them names no
application at all: adding one is a registry entry and a settings file.

The line between the two is what makes that true. What every app has — folders
— the page does generically, through one `saveDirectories` bound to the app.
What one app alone has, its pane does itself with the transport it is handed.
An app that only needs directories touches neither `group-settings.js` nor
`group-page.js`, which is `test_app_settings_plugin.py`'s subject.

`settings-ui.js` exists because a pane importing the page that renders it is a
cycle, and ES modules answer that with a temporal-dead-zone ReferenceError at
first render — a component that silently does not appear, the fault already
recorded in CLAUDE.md about hook ordering.

The flat depth-indented `<select>` of every folder in the library becomes a
modal tree. It asks the node for nothing: the tree is derived from paths the
client already holds, so it shows exactly what the group's index contains and
adds no folder-browsing protocol. For Chat's attachment folder — the one
directory that is written to rather than read — read-only roots are greyed
out, so the node's refusal arrives before the operator picks rather than when
somebody sends a file.

Videos and Music take a list of folders. A library on two drives could not be
described before; the only recourse was pointing the app at a parent containing
both, which pulls in everything else under it. The scalar shapes survive on the
wire alone, for a node speaking MNP 1.0, and the client reads them as a
one-element list.

Two things the tests caught that I would not have:

`test_asset_versioning` — six new modules were missing from `_ASSETS`. Reached
through the registry rather than imported by name, they are exactly the files
nothing else would notice changing, and a stale one is served from cache with
no version bump.

And `node --check foo.js` does **not** reliably report a module syntax error:
it accepted `${/* ... */''}` — htm template syntax pasted into a plain object
literal — and reported success. A `.mjs` copy forces the module parser and
reports it. The suite had no syntax check at all, which is how that reached a
file; `test_spa_syntax.py` does it for every module now, and pins that the
loose path is not what it uses.

Suite: 12 failures, all pre-existing.

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

1 files changed, 27 insertions, 0 deletions

diff --git a/packages/meshbay-hub/src/meshbay_hub/static/locales/it.js b/packages/meshbay-hub/src/meshbay_hub/static/locales/it.js
index 38fc241..e39d91d 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/locales/it.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/locales/it.js
@@ -828,6 +828,33 @@ export default {
   'settings_node.photo_roots_save': 'Salva',
   'settings_node.shared_directories_title': 'Directory condivise',
   'settings_node.shared_directories_hint': 'Cartelle condivise con questo gruppo. Attiva lettura-scrittura per consentire il caricamento, segna come rimovibile per unità esterne.',
+  'folder_tree.title_single': 'Scegli una cartella',
+  'folder_tree.title_multi': 'Scegli le cartelle',
+  'folder_tree.choose': 'Scegli…',
+  'folder_tree.confirm': 'Usa',
+  'folder_tree.expand': 'Espandi',
+  'folder_tree.collapse': 'Comprimi',
+  'folder_tree.nothing_selected': 'Niente selezionato',
+  'folder_tree.empty': 'Questo gruppo non ha ancora directory condivise.',
+  'folder_tree.writable_only': 'Qui si possono scegliere solo directory in lettura-scrittura: ci vengono scritti dei file.',
+  'folder_tree.no_writable_root': 'Questo gruppo non ha directory scrivibili. Attiva prima lettura-scrittura in Directory condivise.',
+  'folder_tree.read_only_blocked': 'Sola lettura: non vi si può scrivere',
+  'settings_app.save': 'Salva',
+  'settings_app.saving': 'Salvataggio…',
+  'settings_app.disabled_hint': 'Attiva questa applicazione per configurarla.',
+  'settings_app.video_directories_label': 'Cartelle video',
+  'settings_app.video_directories_hint': 'Dove si trovano film e serie di questo gruppo. Nulla al di fuori compare nella scheda Video.',
+  'settings_app.music_directories_label': 'Cartelle musica',
+  'settings_app.music_directories_hint': 'Dove si trovano gli album di questo gruppo. Nulla al di fuori compare nella scheda Musica.',
+  'settings_app.photo_directories_label': 'Cartelle foto',
+  'settings_app.photo_directories_hint': 'Dove si trovano gli album di questo gruppo. Nulla al di fuori compare nella scheda Foto.',
+  'settings_app.chat_directory_label': 'Cartella degli allegati',
+  'settings_app.chat_directory_hint': 'Dove vengono scritti i file inviati in chat. Deve essere una directory in lettura-scrittura.',
+  'settings_app.chat_no_writable_root': 'Questo gruppo non ha directory scrivibili, quindi gli allegati sono disattivati.',
+  'settings_app.chat_link_preview_label': 'Anteprime dei link',
+  'settings_app.chat_link_preview_hint': 'Quando un membro pubblica un link, il nodo recupera titolo e immagine della pagina. È una richiesta dalla tua macchina a un sito scelto da qualcun altro.',
+  'settings_app.tmdb_token_prompt': 'Registrati su TMDB per generare la tua chiave API.',
+  'settings_app.tmdb_token_link': 'Ottieni una chiave',
   'settings_node.roots_offline_hint': 'Non connesso al nodo: le modifiche passano dal nodo locale e hanno effetto al successivo ricaricamento.',
   'settings_node.directories_title': 'Directory delle app',
   'settings_node.directories_hint': 'Cartelle condivise, e quale di esse le app Video, Musica e Foto usano come proprio/i punto/i di ingresso.',