feat(clients): let admins set PersistentKeepalive on tunnel clients

model.Client already carries KeepAlive, and every AmneziaWG/WireGuard client
config emitter already writes PersistentKeepalive when it is above zero -- but
nothing in the UI could set it, so it stayed 0 and the line was never emitted.

Without it a peer that goes quiet has nothing to trigger a handshake: WireGuard
only initiates when it has data to send. An idle client stays disconnected
after any interruption -- a NAT mapping timing out, a device sleeping, the
panel restarting -- until the user generates traffic themselves.

New clients default to 25, the conventional value, which also keeps the NAT
mapping open. Existing clients keep whatever they have, and 0 remains valid and
means "do not send keepalives".

frontend/src/pages/clients/ClientFormModal.tsx

@@ -132,6 +132,7 @@ type Values = ClientFormValues & {
   wgAllowedIPs: string;
   awgAllowedIPs: string;
   awgForwardedPorts: string;
+  wgKeepAlive: number;
   secret: string;
   adTag: string;
 };
@@ -168,6 +169,7 @@ const EMPTY: Values = {
   wgAllowedIPs: '',
   awgAllowedIPs: '',
   awgForwardedPorts: '',
+  wgKeepAlive: 25,
   secret: '',
   adTag: '',
 };
@@ -378,6 +380,7 @@ export default function ClientFormModal({
         wgAllowedIPs: wgTunnelIPs ?? client.allowedIPs ?? '',
         awgAllowedIPs: awgTunnelIPs ?? client.allowedIPs ?? '',
         awgForwardedPorts: client.forwardedPorts || '',
+        wgKeepAlive: client.keepAlive ?? 0,
         secret: client.secret || '',
         adTag: client.adTag || '',
       };
@@ -693,6 +696,7 @@ export default function ClientFormModal({
       // so both protocols share this one field set — see wgPrivateKey etc.
       // below and the AmneziaWG-labeled variants of the same inputs.
       clientPayload.privateKey = values.wgPrivateKey;
+      clientPayload.keepAlive = values.wgKeepAlive;
       clientPayload.publicKey = values.wgPublicKey;
       if (values.wgPreSharedKey) {
         clientPayload.preSharedKey = values.wgPreSharedKey;
@@ -1271,6 +1275,13 @@ export default function ClientFormModal({
                               <Input placeholder="10.8.1.2/32" />
                             </FormField>
                           )}
+                          <FormField
+                            name="wgKeepAlive"
+                            label={t('pages.clients.tunnelKeepAlive')}
+                            extra={t('pages.clients.tunnelKeepAliveHint')}
+                          >
+                            <InputNumber min={0} max={65535} style={{ width: '100%' }} />
+                          </FormField>
                           {showAmneziawg && (
                             <FormField
                               name="awgForwardedPorts"

internal/web/translation/ar-EG.json

@@ -874,6 +874,8 @@
       "amneziaWgAllowedIPsHint": "اتركه فارغًا للتعيين التلقائي؛ افصل بين الإدخالات بفواصل",
       "amneziaWgForwardedPorts": "المنافذ المُعاد توجيهها",
       "amneziaWgForwardedPortsHint": "المنافذ/النطاقات المُعاد توجيهها (DNAT) لهذا العميل، مثل 80, 443, 8000-8100. اتركها فارغة إن لم تكن مطلوبة.",
+      "tunnelKeepAlive": "Keepalive (seconds)",
+      "tunnelKeepAliveHint": "How often the client sends a keepalive packet. 25 is the usual value: it holds the NAT mapping open and brings an idle peer back on its own after any drop, including a panel restart. 0 disables it — an idle client then stays disconnected until it sends traffic.",
       "amneziaWgConfig": "إعدادات AmneziaWG",
       "mtprotoSecret": "سر MTProto",
       "mtprotoSecretHint": "سر FakeTLS الخاص بالعميل. أعد التوليد لتغييره.",

internal/web/translation/en-US.json

@@ -874,6 +874,8 @@
       "amneziaWgAllowedIPsHint": "Leave empty to auto-assign; separate entries with commas",
       "amneziaWgForwardedPorts": "Forwarded Ports",
       "amneziaWgForwardedPortsHint": "Ports/ranges DNAT'd to this client, e.g. 80, 443, 8000-8100. Leave empty for none.",
+      "tunnelKeepAlive": "Keepalive (seconds)",
+      "tunnelKeepAliveHint": "How often the client sends a keepalive packet. 25 is the usual value: it holds the NAT mapping open and brings an idle peer back on its own after any drop, including a panel restart. 0 disables it — an idle client then stays disconnected until it sends traffic.",
       "amneziaWgConfig": "AmneziaWG config",
       "mtprotoSecret": "MTProto secret",
       "mtprotoSecretHint": "The client's FakeTLS secret. Regenerate to rotate it.",

internal/web/translation/es-ES.json

@@ -874,6 +874,8 @@
       "amneziaWgAllowedIPsHint": "Déjalo vacío para asignar automáticamente; separa las entradas con comas",
       "amneziaWgForwardedPorts": "Puertos reenviados",
       "amneziaWgForwardedPortsHint": "Puertos/rangos redirigidos (DNAT) a este cliente, p. ej. 80, 443, 8000-8100. Déjalo vacío si no aplica.",
+      "tunnelKeepAlive": "Keepalive (seconds)",
+      "tunnelKeepAliveHint": "How often the client sends a keepalive packet. 25 is the usual value: it holds the NAT mapping open and brings an idle peer back on its own after any drop, including a panel restart. 0 disables it — an idle client then stays disconnected until it sends traffic.",
       "amneziaWgConfig": "Configuración de AmneziaWG",
       "mtprotoSecret": "Secreto MTProto",
       "mtprotoSecretHint": "El secreto FakeTLS del cliente. Vuelve a generarlo para cambiarlo.",

internal/web/translation/fa-IR.json

@@ -874,6 +874,8 @@
       "amneziaWgAllowedIPsHint": "برای تخصیص خودکار خالی بگذارید؛ ورودی‌ها را با کاما جدا کنید",
       "amneziaWgForwardedPorts": "پورت‌های هدایت‌شده",
       "amneziaWgForwardedPortsHint": "پورت‌ها/محدوده‌های DNAT شده به این کلاینت، مثلاً 80, 443, 8000-8100. برای غیرفعال بودن خالی بگذارید.",
+      "tunnelKeepAlive": "Keepalive (seconds)",
+      "tunnelKeepAliveHint": "How often the client sends a keepalive packet. 25 is the usual value: it holds the NAT mapping open and brings an idle peer back on its own after any drop, including a panel restart. 0 disables it — an idle client then stays disconnected until it sends traffic.",
       "amneziaWgConfig": "پیکربندی AmneziaWG",
       "mtprotoSecret": "سکرت MTProto",
       "mtprotoSecretHint": "سکرت FakeTLS این کلاینت. برای تعویض، دوباره تولید کنید.",

internal/web/translation/id-ID.json

@@ -874,6 +874,8 @@
       "amneziaWgAllowedIPsHint": "Biarkan kosong untuk penetapan otomatis; pisahkan entri dengan koma",
       "amneziaWgForwardedPorts": "Port yang Diteruskan",
       "amneziaWgForwardedPortsHint": "Port/rentang yang di-DNAT ke klien ini, mis. 80, 443, 8000-8100. Biarkan kosong jika tidak ada.",
+      "tunnelKeepAlive": "Keepalive (seconds)",
+      "tunnelKeepAliveHint": "How often the client sends a keepalive packet. 25 is the usual value: it holds the NAT mapping open and brings an idle peer back on its own after any drop, including a panel restart. 0 disables it — an idle client then stays disconnected until it sends traffic.",
       "amneziaWgConfig": "Konfigurasi AmneziaWG",
       "mtprotoSecret": "Secret MTProto",
       "mtprotoSecretHint": "Secret FakeTLS klien. Buat ulang untuk menggantinya.",

internal/web/translation/ja-JP.json

@@ -874,6 +874,8 @@
       "amneziaWgAllowedIPsHint": "空欄で自動割り当て。複数指定はカンマ区切り",
       "amneziaWgForwardedPorts": "転送ポート",
       "amneziaWgForwardedPortsHint": "このクライアントに転送するポート/範囲。例: 80, 443, 8000-8100。空欄で転送なし。",
+      "tunnelKeepAlive": "Keepalive (seconds)",
+      "tunnelKeepAliveHint": "How often the client sends a keepalive packet. 25 is the usual value: it holds the NAT mapping open and brings an idle peer back on its own after any drop, including a panel restart. 0 disables it — an idle client then stays disconnected until it sends traffic.",
       "amneziaWgConfig": "AmneziaWG 設定",
       "mtprotoSecret": "MTProto シークレット",
       "mtprotoSecretHint": "このクライアントの FakeTLS シークレット。変更するには再生成します。",

internal/web/translation/pt-BR.json

@@ -874,6 +874,8 @@
       "amneziaWgAllowedIPsHint": "Deixe vazio para atribuir automaticamente; separe as entradas com vírgulas",
       "amneziaWgForwardedPorts": "Portas encaminhadas",
       "amneziaWgForwardedPortsHint": "Portas/intervalos redirecionados (DNAT) para este cliente, ex. 80, 443, 8000-8100. Deixe vazio se não aplicável.",
+      "tunnelKeepAlive": "Keepalive (seconds)",
+      "tunnelKeepAliveHint": "How often the client sends a keepalive packet. 25 is the usual value: it holds the NAT mapping open and brings an idle peer back on its own after any drop, including a panel restart. 0 disables it — an idle client then stays disconnected until it sends traffic.",
       "amneziaWgConfig": "Configuração do AmneziaWG",
       "mtprotoSecret": "Segredo MTProto",
       "mtprotoSecretHint": "O segredo FakeTLS do cliente. Gere novamente para trocá-lo.",

internal/web/translation/ru-RU.json

@@ -874,6 +874,8 @@
       "amneziaWgAllowedIPsHint": "Оставьте пустым для автоназначения; разделяйте записи запятыми",
       "amneziaWgForwardedPorts": "Проброс портов",
       "amneziaWgForwardedPortsHint": "Порты/диапазоны, DNAT'ящиеся на этого клиента, например 80, 443, 8000-8100. Оставьте пустым, если не нужно.",
+      "tunnelKeepAlive": "Keepalive (секунды)",
+      "tunnelKeepAliveHint": "Как часто клиент шлёт keepalive-пакет. Обычное значение 25: оно держит NAT-маппинг открытым и возвращает простаивающий пир сам после любого разрыва, включая рестарт панели. 0 отключает — тогда молчащий клиент остаётся отключённым до первого своего пакета.",
       "amneziaWgConfig": "Конфиг AmneziaWG",
       "mtprotoSecret": "Секрет MTProto",
       "mtprotoSecretHint": "Секрет FakeTLS клиента. Перегенерируйте, чтобы сменить.",

internal/web/translation/tr-TR.json

@@ -874,6 +874,8 @@
       "amneziaWgAllowedIPsHint": "Otomatik atama için boş bırakın; girişleri virgülle ayırın",
       "amneziaWgForwardedPorts": "Yönlendirilen Portlar",
       "amneziaWgForwardedPortsHint": "Bu istemciye DNAT ile yönlendirilen port/aralıklar, örn. 80, 443, 8000-8100. Yoksa boş bırakın.",
+      "tunnelKeepAlive": "Keepalive (seconds)",
+      "tunnelKeepAliveHint": "How often the client sends a keepalive packet. 25 is the usual value: it holds the NAT mapping open and brings an idle peer back on its own after any drop, including a panel restart. 0 disables it — an idle client then stays disconnected until it sends traffic.",
       "amneziaWgConfig": "AmneziaWG Yapılandırması",
       "mtprotoSecret": "MTProto sırrı",
       "mtprotoSecretHint": "İstemcinin FakeTLS sırrı. Değiştirmek için yeniden oluşturun.",

internal/web/translation/uk-UA.json

@@ -874,6 +874,8 @@
       "amneziaWgAllowedIPsHint": "Залиште порожнім для автопризначення; розділяйте записи комами",
       "amneziaWgForwardedPorts": "Перенаправлені порти",
       "amneziaWgForwardedPortsHint": "Порти/діапазони, що перенаправляються (DNAT) на цього клієнта, напр. 80, 443, 8000-8100. Залиште порожнім, якщо не потрібно.",
+      "tunnelKeepAlive": "Keepalive (seconds)",
+      "tunnelKeepAliveHint": "How often the client sends a keepalive packet. 25 is the usual value: it holds the NAT mapping open and brings an idle peer back on its own after any drop, including a panel restart. 0 disables it — an idle client then stays disconnected until it sends traffic.",
       "amneziaWgConfig": "Конфігурація AmneziaWG",
       "mtprotoSecret": "Секрет MTProto",
       "mtprotoSecretHint": "Секрет FakeTLS клієнта. Згенеруйте заново, щоб змінити.",

internal/web/translation/vi-VN.json

@@ -874,6 +874,8 @@
       "amneziaWgAllowedIPsHint": "Để trống để tự động gán; phân tách các mục bằng dấu phẩy",
       "amneziaWgForwardedPorts": "Cổng chuyển tiếp",
       "amneziaWgForwardedPortsHint": "Cổng/dải cổng được chuyển tiếp (DNAT) đến client này, vd. 80, 443, 8000-8100. Để trống nếu không cần.",
+      "tunnelKeepAlive": "Keepalive (seconds)",
+      "tunnelKeepAliveHint": "How often the client sends a keepalive packet. 25 is the usual value: it holds the NAT mapping open and brings an idle peer back on its own after any drop, including a panel restart. 0 disables it — an idle client then stays disconnected until it sends traffic.",
       "amneziaWgConfig": "Cấu hình AmneziaWG",
       "mtprotoSecret": "Secret MTProto",
       "mtprotoSecretHint": "Secret FakeTLS của client. Tạo lại để thay đổi.",

internal/web/translation/zh-CN.json

@@ -874,6 +874,8 @@
       "amneziaWgAllowedIPsHint": "留空则自动分配；多个条目用逗号分隔",
       "amneziaWgForwardedPorts": "转发端口",
       "amneziaWgForwardedPortsHint": "转发到此客户端的端口/范围，例如 80, 443, 8000-8100。留空则不转发。",
+      "tunnelKeepAlive": "Keepalive (seconds)",
+      "tunnelKeepAliveHint": "How often the client sends a keepalive packet. 25 is the usual value: it holds the NAT mapping open and brings an idle peer back on its own after any drop, including a panel restart. 0 disables it — an idle client then stays disconnected until it sends traffic.",
       "amneziaWgConfig": "AmneziaWG 配置",
       "mtprotoSecret": "MTProto 密钥",
       "mtprotoSecretHint": "该客户端的 FakeTLS 密钥。重新生成即可更换。",

internal/web/translation/zh-TW.json

@@ -874,6 +874,8 @@
       "amneziaWgAllowedIPsHint": "留空則自動分配；多個條目用逗號分隔",
       "amneziaWgForwardedPorts": "轉發連接埠",
       "amneziaWgForwardedPortsHint": "轉發到此客戶端的連接埠/範圍，例如 80, 443, 8000-8100。留空則不轉發。",
+      "tunnelKeepAlive": "Keepalive (seconds)",
+      "tunnelKeepAliveHint": "How often the client sends a keepalive packet. 25 is the usual value: it holds the NAT mapping open and brings an idle peer back on its own after any drop, including a panel restart. 0 disables it — an idle client then stays disconnected until it sends traffic.",
       "amneziaWgConfig": "AmneziaWG 設定",
       "mtprotoSecret": "MTProto 金鑰",
       "mtprotoSecretHint": "該用戶端的 FakeTLS 金鑰。重新產生即可更換。",