feat: implement VPN platform management and real protocol services

backend/internal/service/openvpn/openvpn_test.go

@@ -0,0 +1,26 @@
+package openvpn
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestValidateOpenVPNModes(t *testing.T) {
+	cfg, err := New().Validate(map[string]interface{}{"auth_mode": "password", "subnet": "10.8.0.0 255.255.255.0"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if cfg["proto"] != "udp" || cfg["port"] != 1194 {
+		t.Fatalf("defaults not applied: %#v", cfg)
+	}
+	if _, err := New().Validate(map[string]interface{}{"auth_mode": "unknown"}); err == nil {
+		t.Fatal("expected invalid auth mode error")
+	}
+}
+
+func TestCertificateCNIsSafeAndStable(t *testing.T) {
+	cn := certificateCN("张三 / alice@example.com")
+	if !certificateName.MatchString(cn) || !strings.HasPrefix(cn, "u-") {
+		t.Fatalf("unsafe CN: %q", cn)
+	}
+}