Add Playwright e2e smoke test and accessibility checklist

playwright.config.js

@@ -0,0 +1,28 @@
+/**
+ * @package ImageFilters
+ *
+ * Playwright configuration for the e2e smoke test.
+ *
+ * Keeps the footprint minimal: one chromium project, expect() semantics.
+ * BASE_URL is read from the environment so the same config can run against
+ * any local Herd site.
+ */
+const { defineConfig, devices } = require( '@playwright/test' );
+
+const BASE_URL = process.env.BASE_URL || 'http://localhost:8080';
+
+module.exports = defineConfig( {
+    testDir: './tests/playwright',
+    fullyParallel: false,
+    reporter: 'list',
+    use: {
+        baseURL: BASE_URL,
+        headless: true,
+    },
+    projects: [
+        {
+            name: 'chromium',
+            use: { ...devices[ 'Desktop Chrome' ] },
+        },
+    ],
+} );