feat: add message queue for sequential run processing (#501)

Allow sending multiple messages while a run is active. Messages are
queued on the server and processed sequentially after each run
completes. Each completed assistant message triggers speech playback
independently, and the UI shows queue status with a badge indicator.

Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>

packages/client/src/i18n/locales/ja.ts

@@ -117,6 +117,8 @@ export default {
     emptyState: 'Hermes Agent と会話を開始しましょう',
     inputPlaceholder: 'メッセージを入力... (Enter で送信、Shift+Enter で改行)',
     attachFiles: 'ファイルを添付',
+    messageQueue: 'メッセージキュー',
+    removeQueuedMessage: 'キューのメッセージを削除',
     stop: '停止',
     send: '送信',
     contextUsed: 'コンテキスト使用量:',