feat: add session authorization mode configuration (#446)

Add approvals.mode configuration to allow users to enable/disable
session operation authorization. Mode can be 'off' (no auth) or 'manual'
(require auth). Changes trigger automatic gateway restart for config
to take effect.

- Add ApprovalConfig type with mode: 'off' | 'manual'
- Add approvals section to settings store
- Add session authorization toggle in SessionSettings UI
- Add approvals to PLATFORM_SECTIONS for auto-restart
- Add i18n support for all 8 languages

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

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

@@ -475,6 +475,8 @@ export default {
       liveMonitorHumanOnly: 'ライブモニター: 人間のセッションのみ表示',
       liveMonitorHumanOnlyHint: 'ライブモニターでサブエージェントやセッション監視ノイズを既定で隠します',
       atHourHint: '毎日指定時刻にセッションをリセット',
+      requireAuth: 'セッション認証',
+      requireAuthHint: 'セッション操作に認証を必要とする',
     },
     privacy: {
       redactPii: '個人情報のマスキング',