Add active-turn steering (#3394)

* feat(agents): add active-turn steering

Let users choose whether an immediate prompt interrupts or joins the active turn. The daemon owns exact-turn admission, provider delivery, safe fallback, and canonical timeline identity while queueing remains client-side.

* fix(agents): stabilize steering history and replay QA

* fix(agents): preserve steering timeline order

* fix(agents): reconcile resumed provider history

* fix(agents): serialize steering with cancellation

* test(agents): prove Claude multi-tool steering

* test(agents): force explicit history hydration

* fix(agents): flush output before steer admission

packages/app/src/i18n/resources/ja.ts

@@ -97,6 +97,7 @@ export const ja: TranslationResources = {
       interruptAgent: "エージェントを中断",
       queueMessage: "メッセージをキューに追加",
       sendAndInterrupt: "送信して中断",
+      sendAndSteer: "送信して指示を追加",
       sendMessage: "メッセージを送信",
       queue: "キュー",
       send: "送信",
@@ -1841,10 +1842,13 @@ export const ja: TranslationResources = {
         label: "デフォルトの送信",
         descriptions: {
           interrupt: "エージェント実行中、Enterで中断します。Command/Ctrl+Enterでキューに追加。",
+          steer:
+            "エージェント実行中、Enterで現在のターンに指示を送ります。Command/Ctrl+Enterでキューに追加。",
           queue: "エージェント実行中、Enterでキューに追加します。Command/Ctrl+Enterで送信。",
         },
         options: {
           interrupt: "中断",
+          steer: "指示",
           queue: "キュー",
         },
       },