fix: skip validation for user-defined Caddy configs if caddy not running locally

internal/machine/caddyconfig/caddyfile.go

@@ -95,7 +95,11 @@ func NewCaddyfileGenerator(machineID string, validator CaddyfileValidator, log *
 //	[service-a x-caddy]
 //	...
 //	[service-z x-caddy]
-func (g *CaddyfileGenerator) Generate(ctx context.Context, records []store.ContainerRecord) (string, error) {
+//
+// If includeCustom is false, custom Caddy configs (x-caddy) are not included in the generated Caddyfile.
+func (g *CaddyfileGenerator) Generate(
+	ctx context.Context, records []store.ContainerRecord, includeCustom bool,
+) (string, error) {
 	containers := make([]api.ServiceContainer, len(records))
 	for i, cr := range records {
 		containers[i] = cr.Container
@@ -113,6 +117,12 @@ func (g *CaddyfileGenerator) Generate(ctx context.Context, records []store.Conta
 		return "", fmt.Errorf("generate base Caddyfile from service ports: %w", err)
 	}
 
+	if !includeCustom {
+		return fmt.Sprintf("%s\n%s\n"+
+			"# NOTE: User-defined configs for services were skipped because Caddy is not running on this machine.\n",
+			caddyfileHeader, caddyfile), nil
+	}
+
 	upstreams := serviceUpstreams(containers)
 	// Track validation errors for reporting.
 	var configErrors []string