fix: improve mode toggle robustness and add i18n support

- Make mode detection more robust (handle ::1, 0.0.0.0)
- Add getProxyPort() to parse port from ANTHROPIC_BASE_URL dynamically
- Add i18n translation keys for mode toggle in all 5 languages
- Update settings.html to use translation keys and dynamic port

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

public/js/translations/id.js

@@ -409,4 +409,14 @@ window.translations.id = {
     strategyUpdated: "Strategi diubah ke: {strategy}",
     failedToUpdateStrategy: "Gagal memperbarui strategi",
     invalidStrategy: "Strategi tidak valid dipilih",
+    // Mode Toggle (Proxy/Paid)
+    connectionMode: "Mode Koneksi",
+    proxyMode: "Mode Proxy",
+    paidMode: "Mode Berbayar",
+    usingLocalProxy: "Menggunakan server proxy lokal (localhost:{port})",
+    usingOfficialApi: "Menggunakan API resmi Anthropic (memerlukan langganan)",
+    paidModeTitle: "Claude CLI menggunakan API resmi Anthropic",
+    paidModeDesc: "Semua konfigurasi proxy telah dihapus. Claude CLI menggunakan langganan Anthropic Anda secara langsung.",
+    paidModeHint: "Beralih ke mode Proxy untuk mengonfigurasi routing model dan preset.",
+    modeToggleFailed: "Gagal beralih mode",
 };