feat(frontend): confirm before stopping Xray and offer Start when it is stopped (#7104)

Stop sat next to Restart on the dashboard and fired on the first click. A
mis-click cut every proxy connection, and when the panel itself is reached
through that proxy the only way back was SSH (#7103).

Stop now opens a confirmation with Cancel focused. When Xray is stopped the
first button reads Start instead of Restart and Stop is disabled; in the
crashed state Stop stays enabled, because setting the manual-stop flag is
what halts the crash-recovery restart loop.

Closes #7103

internal/web/translation/ja-JP.json

@@ -151,6 +151,11 @@
       "xrayStatus": "Xray",
       "stopXray": "停止",
       "restartXray": "再起動",
+      "startXray": "開始",
+      "stopXrayDisabledHint": "Xray は実行されていません",
+      "stopXrayConfirmTitle": "Xray を停止しますか?",
+      "stopXrayConfirmContent": "Xray を停止すると、すべてのプロキシ接続が直ちに切断されます。続行しますか?",
+      "stopXrayConfirmOk": "Xray を停止",
       "xraySwitch": "バージョン",
       "xrayUpdates": "Xrayの更新",
       "xraySwitchClickDesk": "慎重に選択してください。古いバージョンは現在の設定と互換性がない可能性があります。",