feat: 新增隧道管理功能，前后端完整实现

- 新增统一 ApiResponse 类型定义，与 Rust 端响应结构对齐
- 新增 Rust 后端隧道数据库表、模型、命令和 API 接口
- 新增前端隧道类型定义、API 调用、卡片组件和表单弹窗
- 新增中英双语隧道相关国际化文案
- 更新服务器类型定义，引入共享的 ApiResponse

src/i18n/locales/en-US.json

@@ -88,6 +88,80 @@
       "portRange": "Port must be between 1 and 65535"
     }
   },
+  "tunnel": {
+    "refresh": "Refresh",
+    "add": "Add tunnel",
+    "empty": "No tunnels yet. Click Add in the top right corner.",
+    "edit": "Edit",
+    "delete": "Delete",
+    "deleteConfirm": "Are you sure you want to delete tunnel \"{name}\"?",
+    "name": "Name",
+    "namePlaceholder": "Enter a tunnel name",
+    "type": "Proxy type",
+    "localIp": "Local IP",
+    "localIpPlaceholder": "e.g. 127.0.0.1",
+    "localPort": "Local port",
+    "remotePort": "Remote port",
+    "remotePortTip": "Required for tcp / udp",
+    "pinned": "Pinned",
+    "enabled": "Enabled",
+    "enabledTip": "Multiple tunnels can be enabled at once",
+    "remark": "Remark",
+    "remarkPlaceholder": "Optional remark",
+    "sort": "Sort",
+    "saveSuccess": "Saved successfully",
+    "deleteSuccess": "Deleted successfully",
+    "advanced": "Advanced settings",
+    "customDomains": "Custom domains",
+    "customDomainsPlaceholder": "Type a domain and press Enter to add more",
+    "subdomain": "Subdomain",
+    "subdomainPlaceholder": "e.g. test",
+    "locations": "URL prefixes",
+    "locationsPlaceholder": "Type a URL prefix and press Enter to add more",
+    "secretKey": "Secret key",
+    "secretKeyPlaceholder": "Secret key for stcp / xtcp / sudp",
+    "useEncryption": "Enable encryption",
+    "useCompression": "Enable compression",
+    "bandwidthLimit": "Bandwidth limit",
+    "bandwidthLimitPlaceholder": "e.g. 1MB / 1KB",
+    "proxyProtocolVersion": "Proxy Protocol version",
+    "proxyProtocolVersionDefault": "Disabled",
+    "healthCheck": "Health check",
+    "healthCheckType": "Check type",
+    "healthCheckTypeDefault": "Disabled",
+    "healthCheckTimeout": "Timeout (s)",
+    "healthCheckMaxFailed": "Max failed",
+    "healthCheckInterval": "Interval (s)",
+    "healthCheckPath": "Check path",
+    "healthCheckPathPlaceholder": "e.g. /healthz",
+    "loadBalancer": "Load balancer",
+    "loadBalancerGroup": "Group",
+    "loadBalancerGroupPlaceholder": "Proxies in the same group are load balanced",
+    "loadBalancerGroupKey": "Group key",
+    "local": "Local",
+    "remote": "Remote",
+    "types": {
+      "tcp": "TCP",
+      "udp": "UDP",
+      "http": "HTTP",
+      "https": "HTTPS",
+      "stcp": "STCP (secure TCP)",
+      "xtcp": "XTCP (P2P)",
+      "sudp": "SUDP (secure UDP)",
+      "tcpmux": "TCPMUX"
+    },
+    "form": {
+      "addTitle": "Add tunnel",
+      "editTitle": "Edit tunnel",
+      "nameRequired": "Please enter the tunnel name",
+      "typeRequired": "Please select the proxy type",
+      "localIpRequired": "Please enter the local IP",
+      "localIpInvalid": "Please enter a valid IP address or domain",
+      "localPortRequired": "Please enter the local port",
+      "remotePortRequired": "Please enter the remote port",
+      "portRange": "Port must be between 1 and 65535"
+    }
+  },
   "common": {
     "developing": "This feature is under construction",
     "confirm": "OK",