Terminal: a shell on the agent chat's computer, before the first message too

The Terminal panel opens a shell on the device an agent chat works on, in its
folder: for a new agent chat as soon as the device and folder are chosen (the
server's /api/v2/devices/{device}/terminal/ws?directory=, which the chat's first
message takes over -- the same socket carries on), and for an open agent chat
from the header (/api/v2/chats/{chat}/terminal/ws, the web page's shell).
Offered where GET /devices says the device opens a terminal.

The socket is Rust's (src-tauri/src/terminal.rs, tungstenite on the rustls
ureq already brings): the bearer token goes in the handshake and never reaches
the page, which gets the frames as `terminal` events and sends keys, sizes and
close through commands. 4401 signs the app out as a 401 does.

xterm and its fit addon are the server's vendored build, pinned through
fetch-vendor.sh like CodeMirror and loaded on the first open. Send to chat puts
the selection, the last marked command and its output, or the screen into the
composer, never sent. The terminal and the activity panel take turns in the
panel column. Continue in a terminal stays in the chat's menu.

tests/ui: seven B3 cases with a mocked socket, at 1280 and 390 px.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

scripts/gen-i18n.py

@@ -376,6 +376,29 @@ KEYS = (
     "Nothing runs in the background. Subagents, a team's members and background commands show here while they work.",
     "Team: %(size)s of at most %(max)s subagents",
     "How many work on it at once, the run's own agent among them, on the same model.",
+    # terminal.js
+    "Terminal",
+    "Close terminal",
+    "Send to chat",
+    "Connecting…",
+    "Connected.",
+    "Connected. This shell is also open in another tab, and they share a size.",
+    "Disconnected. Close and reopen to reconnect.",
+    "This terminal closed.",
+    "Reconnecting…",
+    "The terminal could not be loaded.",
+    "Nothing has been run in this shell yet.",
+    "Nothing to send: select some output first.",
+    "Copied the last of the screen, as it appeared. This shell does not mark where commands begin.",
+    "Copied.",
+    "The previous command",
+    "The previous command (Ctrl+Shift+↑)",
+    "The next command",
+    "The next command (Ctrl+Shift+↓)",
+    "Copy the last command and its output",
+    "Put the last command and its output into the message box",
+    "Sign in again: the server no longer accepts this app's sign-in.",
+    "The terminal needs a newer LLeMbas server. Ask its administrator to update it.",
 )
 
 # The app's own sentences. The mode names (Manual, Edit, Auto, Plan) stay English, as the
@@ -383,6 +406,8 @@ KEYS = (
 # the device, as the server's catalogue has it.
 OWN: dict[str, dict[str, str]] = {
     "cs": {
+        "Sign in again: the server no longer accepts this app's sign-in.": "Přihlaste se znovu: server už nepřijímá přihlášení této aplikace.",
+        "The terminal needs a newer LLeMbas server. Ask its administrator to update it.": "Terminál potřebuje novější server LLeMbas. Požádejte jeho správce o aktualizaci.",
         "This model serves one request at a time: subagents need another model, on another server, named in the chat.": "Tento model vyřizuje najednou jeden požadavek: podagenti potřebují jiný model na jiném serveru, pojmenovaný v konverzaci.",
         "The numbers count this chat's own agent: 1 is the agent alone, with no subagents; Max 4 is the agent and up to 3 subagents. A subagent runs on the chat's model, or on another only when you name it in the chat.": "Čísla počítají i vlastního agenta konverzace: 1 je agent sám, bez podagentů; Max 4 je agent a až 3 podagenti. Podagent běží na modelu konverzace, na jiném jen tehdy, když ho v konverzaci pojmenujete.",
         "Min": "Min",
@@ -604,6 +629,8 @@ OWN: dict[str, dict[str, str]] = {
         "No day ticked: every day.": "Žádný den nezaškrtnutý: každý den.",
     },
     "de": {
+        "Sign in again: the server no longer accepts this app's sign-in.": "Melden Sie sich erneut an: Der Server nimmt die Anmeldung dieser App nicht mehr an.",
+        "The terminal needs a newer LLeMbas server. Ask its administrator to update it.": "Das Terminal braucht einen neueren LLeMbas-Server. Bitten Sie seinen Administrator, ihn zu aktualisieren.",
         "This model serves one request at a time: subagents need another model, on another server, named in the chat.": "Dieses Modell bedient eine Anfrage zur Zeit: Subagenten brauchen ein anderes Modell auf einem anderen Server, im Chat genannt.",
         "The numbers count this chat's own agent: 1 is the agent alone, with no subagents; Max 4 is the agent and up to 3 subagents. A subagent runs on the chat's model, or on another only when you name it in the chat.": "Die Zahlen zählen den eigenen Agenten des Chats mit: 1 ist der Agent allein, ohne Subagenten; Max 4 ist der Agent und bis zu 3 Subagenten. Ein Subagent läuft auf dem Modell des Chats, auf einem anderen nur, wenn Sie es im Chat nennen.",
         "Min": "Min",
@@ -825,6 +852,8 @@ OWN: dict[str, dict[str, str]] = {
         "No day ticked: every day.": "Kein Tag angehakt: jeden Tag.",
     },
     "es": {
+        "Sign in again: the server no longer accepts this app's sign-in.": "Vuelva a iniciar sesión: el servidor ya no acepta el inicio de sesión de esta aplicación.",
+        "The terminal needs a newer LLeMbas server. Ask its administrator to update it.": "El terminal necesita un servidor LLeMbas más reciente. Pida a su administrador que lo actualice.",
         "This model serves one request at a time: subagents need another model, on another server, named in the chat.": "Este modelo atiende una petición a la vez: los subagentes necesitan otro modelo, en otro servidor, nombrado en el chat.",
         "The numbers count this chat's own agent: 1 is the agent alone, with no subagents; Max 4 is the agent and up to 3 subagents. A subagent runs on the chat's model, or on another only when you name it in the chat.": "Los números cuentan el agente propio del chat: 1 es el agente solo, sin subagentes; Máx. 4 es el agente y hasta 3 subagentes. Un subagente usa el modelo del chat, u otro solo si lo nombra en el chat.",
         "Min": "Mín.",
@@ -1046,6 +1075,8 @@ OWN: dict[str, dict[str, str]] = {
         "No day ticked: every day.": "Ningún día marcado: todos los días.",
     },
     "fr": {
+        "Sign in again: the server no longer accepts this app's sign-in.": "Reconnectez-vous : le serveur n’accepte plus la connexion de cette application.",
+        "The terminal needs a newer LLeMbas server. Ask its administrator to update it.": "Le terminal nécessite un serveur LLeMbas plus récent. Demandez à son administrateur de le mettre à jour.",
         "This model serves one request at a time: subagents need another model, on another server, named in the chat.": "Ce modèle traite une requête à la fois : les sous-agents ont besoin d’un autre modèle, sur un autre serveur, nommé dans la conversation.",
         "The numbers count this chat's own agent: 1 is the agent alone, with no subagents; Max 4 is the agent and up to 3 subagents. A subagent runs on the chat's model, or on another only when you name it in the chat.": "Les nombres comptent l’agent de la conversation : 1, c’est l’agent seul, sans sous-agents ; Max 4, c’est l’agent et jusqu’à 3 sous-agents. Un sous-agent utilise le modèle de la conversation, ou un autre seulement si vous le nommez dans la conversation.",
         "Min": "Min",
@@ -1267,6 +1298,8 @@ OWN: dict[str, dict[str, str]] = {
         "No day ticked: every day.": "Aucun jour coché : tous les jours.",
     },
     "hu": {
+        "Sign in again: the server no longer accepts this app's sign-in.": "Jelentkezzen be újra: a szerver már nem fogadja el ennek az alkalmazásnak a bejelentkezését.",
+        "The terminal needs a newer LLeMbas server. Ask its administrator to update it.": "A terminálhoz újabb LLeMbas-szerver kell. Kérje meg a rendszergazdáját, hogy frissítse.",
         "This model serves one request at a time: subagents need another model, on another server, named in the chat.": "Ez a modell egyszerre egy kérést szolgál ki: az alügynököknek másik modell kell, másik szerveren, a beszélgetésben megnevezve.",
         "The numbers count this chat's own agent: 1 is the agent alone, with no subagents; Max 4 is the agent and up to 3 subagents. A subagent runs on the chat's model, or on another only when you name it in the chat.": "A számokba a beszélgetés saját ügynöke is beleszámít: az 1 maga az ügynök, alügynökök nélkül; a Max. 4 az ügynök és legfeljebb 3 alügynök. Az alügynök a beszélgetés modelljén fut, másikon csak akkor, ha megnevezi a beszélgetésben.",
         "Min": "Min.",
@@ -1488,6 +1521,8 @@ OWN: dict[str, dict[str, str]] = {
         "No day ticked: every day.": "Ha egy nap sincs bejelölve: minden nap.",
     },
     "it": {
+        "Sign in again: the server no longer accepts this app's sign-in.": "Accedi di nuovo: il server non accetta più l’accesso di questa app.",
+        "The terminal needs a newer LLeMbas server. Ask its administrator to update it.": "Il terminale richiede un server LLeMbas più recente. Chiedi al suo amministratore di aggiornarlo.",
         "This model serves one request at a time: subagents need another model, on another server, named in the chat.": "Questo modello serve una richiesta alla volta: i sottoagenti hanno bisogno di un altro modello, su un altro server, nominato nella chat.",
         "The numbers count this chat's own agent: 1 is the agent alone, with no subagents; Max 4 is the agent and up to 3 subagents. A subagent runs on the chat's model, or on another only when you name it in the chat.": "I numeri contano anche l’agente della chat: 1 è l’agente da solo, senza sottoagenti; Max 4 è l’agente più fino a 3 sottoagenti. Un sottoagente usa il modello della chat, o un altro solo se lo nomini nella chat.",
         "Min": "Min",
@@ -1709,6 +1744,8 @@ OWN: dict[str, dict[str, str]] = {
         "No day ticked: every day.": "Nessun giorno spuntato: ogni giorno.",
     },
     "pl": {
+        "Sign in again: the server no longer accepts this app's sign-in.": "Zaloguj się ponownie: serwer nie przyjmuje już logowania tej aplikacji.",
+        "The terminal needs a newer LLeMbas server. Ask its administrator to update it.": "Terminal wymaga nowszego serwera LLeMbas. Poproś jego administratora o aktualizację.",
         "This model serves one request at a time: subagents need another model, on another server, named in the chat.": "Ten model obsługuje jedno żądanie naraz: podagenci potrzebują innego modelu, na innym serwerze, wskazanego w czacie.",
         "The numbers count this chat's own agent: 1 is the agent alone, with no subagents; Max 4 is the agent and up to 3 subagents. A subagent runs on the chat's model, or on another only when you name it in the chat.": "Liczby obejmują własnego agenta czatu: 1 to sam agent, bez podagentów; Maks 4 to agent i do 3 podagentów. Podagent działa na modelu czatu, na innym tylko wtedy, gdy wskażesz go w czacie.",
         "Min": "Min",
@@ -1930,6 +1967,8 @@ OWN: dict[str, dict[str, str]] = {
         "No day ticked: every day.": "Żaden dzień niezaznaczony: codziennie.",
     },
     "sk": {
+        "Sign in again: the server no longer accepts this app's sign-in.": "Prihláste sa znova: server už neprijíma prihlásenie tejto aplikácie.",
+        "The terminal needs a newer LLeMbas server. Ask its administrator to update it.": "Terminál potrebuje novší server LLeMbas. Požiadajte jeho správcu o aktualizáciu.",
         "This model serves one request at a time: subagents need another model, on another server, named in the chat.": "Tento model vybavuje naraz jednu požiadavku: podagenti potrebujú iný model na inom serveri, pomenovaný v konverzácii.",
         "The numbers count this chat's own agent: 1 is the agent alone, with no subagents; Max 4 is the agent and up to 3 subagents. A subagent runs on the chat's model, or on another only when you name it in the chat.": "Čísla počítajú aj vlastného agenta konverzácie: 1 je agent sám, bez podagentov; Max 4 je agent a až 3 podagenti. Podagent beží na modeli konverzácie, na inom len vtedy, keď ho v konverzácii pomenujete.",
         "Min": "Min",