i18n(chat): translate the chat send/receive toasts into all 8 languages

The HushChat UI labels were already translated, but the send-path
notifications (not-connected, no-z-address, waiting-for-reply, compose
failures, contact-request queued, lite busy) were still hardcoded English.
Route all eight call sites in app_network.cpp through TR() with seven new
keys (the three "no z-address" variants unified into chat_toast_no_zaddr),
add the English fallbacks in i18n.cpp, and translate the keys into de/es/fr/
ja/ko/pt/ru/zh — reusing each file's existing chat_* terminology (z-address,
contact request, message) for consistency. Additive only (950 -> 957 keys
per language). CJK subset font rebuilt to cover the new zh/ja/ko glyphs.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

res/lang/es.json

@@ -123,6 +123,13 @@
     "chat_select_hint": "Selecciona una conversación para verla.",
     "chat_send": "Enviar",
     "chat_send_failed": "no enviado",
+    "chat_toast_compose_failed": "No se pudo componer el mensaje (¿demasiado largo?).",
+    "chat_toast_lite_busy": "Ya hay un envío en curso, o no hay ningún monedero abierto.",
+    "chat_toast_no_zaddr": "No hay ninguna dirección z disponible desde la que enviar el chat.",
+    "chat_toast_not_connected": "Sin conexión: mensaje de chat no enviado.",
+    "chat_toast_request_compose_failed": "No se pudo componer la solicitud de contacto (¿dirección o texto no válidos?).",
+    "chat_toast_request_queued": "Solicitud de contacto en cola.",
+    "chat_toast_waiting_reply": "Espera a que este contacto responda antes de poder escribirle.",
     "chat_waiting_reply": "Esperando a que este contacto responda: podrás escribirle una vez lo haga.",
     "chat_you": "Tú",
     "choose_icon": "Elegir Icono",