feat: make TLS optional in Barkfile schema

validate.go

@@ -21,11 +21,10 @@ func (c Config) Validate() error {
 	} else if err := validateListenAddress(c.Listen); err != nil {
 		errs = append(errs, fmt.Errorf("listen address %q: %w", c.Listen, err))
 	}
-	if strings.TrimSpace(c.TLS.CertFile) == "" {
-		errs = append(errs, errors.New("TLS certificate is required"))
-	}
-	if strings.TrimSpace(c.TLS.KeyFile) == "" {
-		errs = append(errs, errors.New("TLS private key is required"))
+	certificateSet := strings.TrimSpace(c.TLS.CertFile) != ""
+	keySet := strings.TrimSpace(c.TLS.KeyFile) != ""
+	if certificateSet != keySet {
+		errs = append(errs, errors.New("tls requires both cert and key"))
 	}
 	if len(c.Databases) == 0 {
 		errs = append(errs, errors.New("at least one database route is required"))