test: remove the legacy ECS test layer and its harness

qa/pom.xml

@@ -77,23 +77,14 @@
             <version>${project.version}</version>
             <scope>test</scope>
         </dependency>
-        <!-- The PDF backend (provider on the classpath so the relocated render
-             suites resolve a backend) plus its tests-classifier jar, which carries
-             the shared render harness (EngineComposerHarness + engine.assembly). -->
+        <!-- The PDF backend — the provider on the classpath so the relocated
+             render suites resolve a backend and can build/rasterize PDFs. -->
         <dependency>
             <groupId>io.github.demchaav</groupId>
             <artifactId>graph-compose-render-pdf</artifactId>
             <version>${project.version}</version>
             <scope>test</scope>
         </dependency>
-        <dependency>
-            <groupId>io.github.demchaav</groupId>
-            <artifactId>graph-compose-render-pdf</artifactId>
-            <version>${project.version}</version>
-            <type>test-jar</type>
-            <classifier>tests</classifier>
-            <scope>test</scope>
-        </dependency>
         <!-- The built-in templates (the relocated visual-parity + smoke suites
              render them) plus their tests-classifier jar, which carries the template
              data fixtures (com.demcha.mock.*DataFixtures). -->

qa/src/test/java/com/demcha/compose/document/api/BarcodeRenderTest.java

@@ -0,0 +1,38 @@
+package com.demcha.compose.document.api;
+
+import com.demcha.compose.GraphCompose;
+import com.demcha.compose.document.layout.LayoutGraph;
+import com.demcha.compose.document.style.DocumentInsets;
+import org.junit.jupiter.api.Test;
+
+import java.nio.charset.StandardCharsets;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * End-to-end coverage for the canonical barcode DSL ({@code addBarcode}): a QR
+ * code and a linear CODE128 both lay out on a single page and render through the
+ * PDF backend without error. Guards barcode rendering on the canonical path.
+ */
+class BarcodeRenderTest {
+
+    @Test
+    void barcodesLayOutOnOnePageAndRenderToPdf() throws Exception {
+        try (DocumentSession session = GraphCompose.document()
+                .pageSize(240, 200)
+                .margin(DocumentInsets.of(12))
+                .create()) {
+            session.pageFlow()
+                    .addBarcode(b -> b.qrCode().data("GC-2026-001").size(80, 80))
+                    .addBarcode(b -> b.code128().data("GC-2026-001").size(160, 40))
+                    .build();
+
+            LayoutGraph graph = session.layoutGraph();
+            assertThat(graph.totalPages()).isEqualTo(1);
+            assertThat(graph.nodes()).isNotEmpty();
+
+            byte[] pdf = session.toPdfBytes();
+            assertThat(new String(pdf, 0, 5, StandardCharsets.US_ASCII)).isEqualTo("%PDF-");
+        }
+    }
+}