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/zh-CN.json

@@ -151,6 +151,11 @@
       "xrayStatus": "Xray",
       "stopXray": "停止",
       "restartXray": "重启",
+      "startXray": "启动",
+      "stopXrayDisabledHint": "Xray 未运行",
+      "stopXrayConfirmTitle": "停止 Xray?",
+      "stopXrayConfirmContent": "停止 Xray 将立即中断所有代理连接。确定要继续吗?",
+      "stopXrayConfirmOk": "停止 Xray",
       "xraySwitch": "版本",
       "xrayUpdates": "Xray 更新",
       "xraySwitchClickDesk": "请谨慎选择，因为较旧版本可能与当前配置不兼容",