feat(vpn): add VPN server management and route-based VPN access control

ts_interfaces/data/vpn.ts

@@ -0,0 +1,45 @@
+/**
+ * A registered VPN client (secrets excluded from API responses).
+ */
+export interface IVpnClient {
+  clientId: string;
+  enabled: boolean;
+  tags?: string[];
+  description?: string;
+  assignedIp?: string;
+  createdAt: number;
+  updatedAt: number;
+  expiresAt?: string;
+}
+
+/**
+ * VPN server status.
+ */
+export interface IVpnServerStatus {
+  running: boolean;
+  forwardingMode: 'tun' | 'socket';
+  subnet: string;
+  wgListenPort: number;
+  serverPublicKeys: {
+    noisePublicKey: string;
+    wgPublicKey: string;
+  } | null;
+  registeredClients: number;
+  connectedClients: number;
+}
+
+/**
+ * VPN client telemetry data.
+ */
+export interface IVpnClientTelemetry {
+  clientId: string;
+  assignedIp: string;
+  bytesSent: number;
+  bytesReceived: number;
+  packetsDropped: number;
+  bytesDropped: number;
+  lastKeepaliveAt?: string;
+  keepalivesReceived: number;
+  rateLimitBytesPerSec?: number;
+  burstBytes?: number;
+}