fix: allow disabling trace export

internal/config/config.go

@@ -269,7 +269,7 @@ func Load(serviceName string) (Config, error) {
 		AuthIssuerURL:           stringEnv("AUTH_ISSUER_URL", "http://localhost:58180/realms/voice-local"),
 		AuthJWKSURL:             stringEnv("AUTH_JWKS_URL", "http://localhost:58180/realms/voice-local/protocol/openid-connect/certs"),
 		AuthAudience:            stringEnv("AUTH_AUDIENCE", "voice-platform-web"),
-		OTLPEndpoint:            stringEnv("OTEL_EXPORTER_OTLP_ENDPOINT", "localhost:54317"),
+		OTLPEndpoint:            stringEnvAllowEmpty("OTEL_EXPORTER_OTLP_ENDPOINT", "localhost:54317"),
 		DependencyTimeout:       dependencyTimeout,
 		ExternalProbeInterval:   externalProbeInterval,
 		ShutdownTimeout:         shutdownTimeout,
@@ -703,6 +703,14 @@ func stringEnv(key, fallback string) string {
 	return value
 }
 
+func stringEnvAllowEmpty(key, fallback string) string {
+	value, exists := os.LookupEnv(key)
+	if !exists {
+		return fallback
+	}
+	return strings.TrimSpace(value)
+}
+
 func intEnv(key string, fallback int) (int, error) {
 	value := strings.TrimSpace(os.Getenv(key))
 	if value == "" {

internal/config/config_test.go

@@ -27,6 +27,17 @@ func TestLoadUsesServicePortDefaults(t *testing.T) {
 	}
 }
 
+func TestLoadAllowsTracingExporterToBeDisabled(t *testing.T) {
+	t.Setenv("OTEL_EXPORTER_OTLP_ENDPOINT", "")
+	cfg, err := Load("api")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if cfg.OTLPEndpoint != "" {
+		t.Fatalf("OTLPEndpoint = %q, want disabled exporter", cfg.OTLPEndpoint)
+	}
+}
+
 func TestLoadRejectsInvalidDuration(t *testing.T) {
 	t.Setenv("DEPENDENCY_TIMEOUT", "soon")
 	if _, err := Load("api"); err == nil {