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/zh.json

@@ -123,6 +123,13 @@
     "chat_select_hint": "选择一个对话以查看。",
     "chat_send": "发送",
     "chat_send_failed": "未发送",
+    "chat_toast_compose_failed": "无法编写该消息（内容过长？）。",
+    "chat_toast_lite_busy": "已有发送正在进行中，或未打开任何钱包。",
+    "chat_toast_no_zaddr": "没有可用于发送聊天的 z 地址。",
+    "chat_toast_not_connected": "未连接——聊天消息未发送。",
+    "chat_toast_request_compose_failed": "无法编写联系人请求（地址或文本无效？）。",
+    "chat_toast_request_queued": "联系人请求已排队。",
+    "chat_toast_waiting_reply": "等待该联系人回复——对方回复后您即可向其发送消息。",
     "chat_waiting_reply": "等待该联系人回复——对方回复后您即可向其发送消息。",
     "chat_you": "我",
     "choose_icon": "选择图标",