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/fr.json

@@ -123,6 +123,13 @@
     "chat_select_hint": "Sélectionnez une conversation pour l'afficher.",
     "chat_send": "Envoyer",
     "chat_send_failed": "non envoyé",
+    "chat_toast_compose_failed": "Impossible de composer le message (trop long ?).",
+    "chat_toast_lite_busy": "Un envoi est déjà en cours, ou aucun portefeuille n'est ouvert.",
+    "chat_toast_no_zaddr": "Aucune adresse Z disponible pour envoyer le message.",
+    "chat_toast_not_connected": "Non connecté — message non envoyé.",
+    "chat_toast_request_compose_failed": "Impossible de composer la demande de contact (adresse / texte invalide ?).",
+    "chat_toast_request_queued": "Demande de contact mise en file d'attente.",
+    "chat_toast_waiting_reply": "En attente de la réponse de ce contact avant de pouvoir lui écrire.",
     "chat_waiting_reply": "En attente de la réponse de ce contact — vous pourrez lui écrire dès qu'il aura répondu.",
     "chat_you": "Vous",
     "choose_icon": "Choisir une icône",