Add Electron test harness with example plugin

test/electron/main.js

@@ -0,0 +1,27 @@
+const { app, BrowserWindow } = require('electron');
+const path = require('path');
+
+/**
+ * Creates the main application window.
+ * nodeIntegration is enabled so the renderer can use require() / dynamic import()
+ * directly against the local node_modules — appropriate for a local test harness.
+ */
+function createWindow() {
+  const win = new BrowserWindow({
+    width: 1200,
+    height: 800,
+    backgroundColor: '#1a1a2e',
+    webPreferences: {
+      nodeIntegration: true,
+      contextIsolation: false,
+    },
+  });
+
+  win.loadFile(path.join(__dirname, 'index.html'));
+}
+
+app.whenReady().then(createWindow);
+
+app.on('window-all-closed', () => {
+  if (process.platform !== 'darwin') app.quit();
+});