feat(openvpn): suggest available OIDC ports and add deployment assets

backend/internal/api/api.go

@@ -230,6 +230,7 @@ func (s *Server) RegisterRoutes(r *gin.Engine) {
 		auth.GET("/readiness", s.readiness)
 		auth.GET("/protocols", s.listProtocols)
 		auth.GET("/tunnels", s.listTunnels)
+		auth.GET("/tunnels/openvpn/oidc-port", s.nextOIDCPort)
 		auth.GET("/tunnels/:id", s.getTunnel)
 		auth.GET("/tunnels/:id/status", s.tunnelStatus)
 		auth.GET("/tunnels/:id/traffic/history", s.tunnelTrafficHistory)