fix(voice): address review of typed AI chat

Typed chat sessions no longer end on the voice inactivity timeout, and a
failed or stopped reply keeps the conversation: Stop cancels only the
reply in progress, and map actions that already ran stay in the model's
context. Each upstream request and map action gets its own deadline, old
tool results shrink instead of the history overflowing, and step limits,
a missing or rejected key, the OAuth lock and throttling each get their
own message.

- Server: OpenAI chat is off under GEV_PREFER_CODEX_OAUTH; chat throttles
  default to the provider's throttle; replies carry API_KEY_MISSING,
  API_KEY_REJECTED, CODEX_OAUTH_REQUIRED and RATE_LIMITED codes; upstream
  Retry-After passes through, and a rejected key (Gemini's invalid-key 400
  included) cools down for a minute
- Pinokio forwards the chat throttle settings
- UI: the reply reveal publishes only the message list; the border orbit
  runs only while busy; layers attach with a button or Enter; the log is
  aria-busy while a reply types out; auto-scroll respects a reader who
  scrolled up; Escape closes the attach menu; the chat gear says Settings;
  a note says chat bills the OpenAI key when voice uses ChatGPT sign-in
- Layout does less work while panel height animates; unused blurs removed
- Gemini voice start ends chat; the voice preview clears on every new
  session
- Tests for the route gates, client limits, attachments and the fixes

src/i18n/locales/ja.json

@@ -2936,5 +2936,12 @@
   "The selected AI provider is shared by voice and chat.": "選んだ AI プロバイダーは音声とチャットで共通です。",
   "Show quick commands": "クイックコマンドを表示",
   "Chat replies are silent. No microphone access is needed.": "チャットの応答は音声なしです。マイクへのアクセスは不要です。",
-  "Chat": "チャット"
+  "Chat": "チャット",
+  "Attach layer": "レイヤーを添付",
+  "Typed chat uses your OpenAI API key. ChatGPT sign-in covers voice only.": "テキストチャットは OpenAI API キーを使用します。ChatGPT のサインインは音声のみが対象です。",
+  "Typed chat is unavailable while GEV_PREFER_CODEX_OAUTH requires ChatGPT OAuth.": "GEV_PREFER_CODEX_OAUTH が ChatGPT OAuth を必須にしている間、テキストチャットは使えません。",
+  "That request needed too many steps. Changes already made to the map stay in place.": "このリクエストは手順が多すぎました。地図に加えた変更はそのまま残ります。",
+  "That request needed too many steps. Try a simpler request.": "このリクエストは手順が多すぎました。より簡単なリクエストを試してください。",
+  "The provider rejected the API key. Check it in Provider Settings.": "プロバイダーが API キーを拒否しました。プロバイダー設定で確認してください。",
+  "Too many chat requests. Try again in {seconds} s.": "チャットのリクエストが多すぎます。{seconds} 秒後にもう一度お試しください。"
 }