HTML artifacts: render agent-sent HTML/CSS/JS code blocks in an in-app WebView (Android platform WebView, desktop JCEF/KCEF) via a full-screen preview; artifact card with Preview button + code toggle, shown only once the message stops streaming; webview-multiplatform 1.9.40 + KCEF deps, detection + unit tests

app/desktopApp/build.gradle.kts

@@ -28,6 +28,16 @@ compose.desktop {
     }
 }
 
+// M9: KCEF (JCEF/Chromium) for HTML artifact previews needs AWT reflection
+// access on modern JDKs. Applied to the `run` task (JavaExec) and, below, to
+// the jpackage `--java-options`.
+afterEvaluate {
+    tasks.withType<JavaExec> {
+        jvmArgs("--add-opens", "java.desktop/sun.awt=ALL-UNNAMED")
+        jvmArgs("--add-opens", "java.desktop/java.awt.peer=ALL-UNNAMED")
+    }
+}
+
 // ── M6: native packaging (docs/11 §11.4) ─────────────────────────────────
 // `./gradlew :desktopApp:jpackage` builds a self-contained app image under
 // build/jpackage (JRE bundled). `./gradlew :desktopApp:jpackage
@@ -78,5 +88,8 @@ tasks.register<Exec>("jpackage") {
         "--icon", file("src/main/resources/icon.png").absolutePath,
         "--dest", destDir.absolutePath,
         "--java-options", "-Xmx1g",
+        // M9: KCEF (JCEF) AWT reflection access (see the JavaExec block above).
+        "--java-options", "--add-opens=java.desktop/sun.awt=ALL-UNNAMED",
+        "--java-options", "--add-opens=java.desktop/java.awt.peer=ALL-UNNAMED",
     )
 }