test: add Playwright smoke test starter

genesis/webui/frontend/package.json

@@ -8,6 +8,7 @@
     "server": "tsx server/index.ts",
     "dev:all": "concurrently \"npm run dev\" \"npm run server\"",
     "build": "tsc -b && oxlint . && vite build",
+    "test:e2e": "playwright test",
     "lint": "eslint .",
     "lint:oxc": "oxlint .",
     "lint:fix": "eslint . --fix",
@@ -41,6 +42,7 @@
     "react-dom": "^19.1.1",
     "react-plotly.js": "^2.6.0",
     "react-router-dom": "^7.9.4",
+    "tailwind-merge": "^3.3.1",
     "tsx": "^4.20.6"
   },
   "devDependencies": {

genesis/webui/frontend/tests/smoke.spec.ts

@@ -0,0 +1,35 @@
+import { expect, test } from '@playwright/test';
+
+test('loads the shell and empty state without a database', async ({ page }) => {
+  await page.route('http://localhost:8000/list_databases', async (route) => {
+    await route.fulfill({
+      status: 200,
+      contentType: 'application/json',
+      body: JSON.stringify([]),
+    });
+  });
+
+  await page.route('http://localhost:8000/get_programs**', async (route) => {
+    await route.fulfill({
+      status: 200,
+      contentType: 'application/json',
+      body: JSON.stringify([]),
+    });
+  });
+
+  await page.goto('/');
+
+  await expect(
+    page.getByRole('heading', { name: 'Genesis', exact: true })
+  ).toBeVisible();
+  await expect(
+    page.getByRole('button', { name: 'Search', exact: true })
+  ).toBeVisible();
+  await expect(
+    page.getByRole('heading', { name: 'No Database Selected', exact: true })
+  ).toBeVisible();
+
+  await page.getByRole('button', { name: 'Search', exact: true }).click();
+
+  await expect(page.getByRole('option', { name: 'Tree View' })).toBeVisible();
+});