fix(webhook): preserve trace context across async detach via WithoutCancel

pkg/modules/webhook/async_context_test.go

@@ -5,9 +5,37 @@ import (
 	"testing"
 	"time"
 
+	"go.opentelemetry.io/otel/trace"
+
 	"github.com/gotenberg/gotenberg/v8/pkg/modules/api"
 )
 
+func TestDetachAsyncContext_PreservesTraceContext(t *testing.T) {
+	traceID, _ := trace.TraceIDFromHex("0123456789abcdef0123456789abcdef")
+	spanID, _ := trace.SpanIDFromHex("0123456789abcdef")
+	sc := trace.NewSpanContext(trace.SpanContextConfig{
+		TraceID:    traceID,
+		SpanID:     spanID,
+		TraceFlags: trace.FlagsSampled,
+		Remote:     true,
+	})
+
+	reqCtx, reqCancel := context.WithDeadline(
+		trace.ContextWithSpanContext(context.Background(), sc),
+		time.Now().Add(2*time.Hour),
+	)
+	defer reqCancel()
+
+	ctx := &api.Context{Context: reqCtx}
+	cancel := detachAsyncContext(ctx, func() {})
+	defer cancel()
+
+	got := trace.SpanContextFromContext(ctx.Context)
+	if got.TraceID() != sc.TraceID() {
+		t.Errorf("expected the detached context to keep trace id %s, got %s", sc.TraceID(), got.TraceID())
+	}
+}
+
 func TestDetachAsyncContext_PreservesDeadline(t *testing.T) {
 	deadline := time.Now().Add(2 * time.Hour)
 	reqCtx, reqCancel := context.WithDeadline(context.Background(), deadline)