feat(outbound): add real-delay connection test mode

The HTTP probe reports the warm per-request round-trip, which reads
lower than the delay figure client apps show for the same server. Add a
third "real" test mode that reuses the temp-instance HTTP probe but
reports the cold request's full elapsed time - tunnel establishment
included - and skips the warm request. UDP-transport outbounds forced
out of the TCP lane still report "http"; in real mode they report
"real". The mode joins the TCP/HTTP toggle on the outbounds tab, with
the label translated in all 13 locales.

internal/web/translation/ja-JP.json

@@ -1627,7 +1627,8 @@
         "testSuccess": "テスト成功",
         "testFailed": "テスト失敗",
         "testError": "アウトバウンドのテストに失敗しました",
-        "testModeTooltip": "TCP: 高速 dial-only プローブ。HTTP: xray を経由した完全リクエスト。",
+        "modeRealDelay": "実際の遅延",
+        "testModeTooltip": "TCP: 高速 dial-only プローブ。HTTP: xray を経由した完全リクエスト。実際の遅延: 接続確立を含む合計時間。",
         "testAll": "すべてテスト",
         "httpStatus": "HTTPステータス",
         "breakdownConnect": "プロキシ接続",