add basic e2e tests

e2e/playwright.config.ts

@@ -0,0 +1,43 @@
+import { defineConfig, devices } from '@playwright/test';
+import path from 'node:path';
+
+const port = Number(process.env.E2E_PORT ?? 4173);
+const baseURL = process.env.E2E_BASE_URL ?? `http://127.0.0.1:${port}`;
+const useWebServer = process.env.E2E_USE_WEBSERVER !== 'false';
+
+export default defineConfig({
+  testDir: path.join(__dirname, 'tests'),
+  outputDir: path.join(__dirname, 'test-results'),
+  fullyParallel: true,
+  forbidOnly: Boolean(process.env.CI),
+  retries: process.env.CI ? 2 : 0,
+  workers: process.env.CI ? 2 : undefined,
+  timeout: 30_000,
+  reporter: [
+    ['list'],
+    ['html', { outputFolder: path.join(__dirname, 'playwright-report'), open: 'never' }],
+  ],
+  use: {
+    baseURL,
+    trace: 'on-first-retry',
+    screenshot: 'only-on-failure',
+    video: 'retain-on-failure',
+  },
+  ...(useWebServer
+    ? {
+        webServer: {
+          command: `node ./node_modules/vite/bin/vite.js --host 127.0.0.1 --port ${port}`,
+          cwd: path.resolve(__dirname, '../frontend'),
+          port,
+          timeout: 120_000,
+          reuseExistingServer: !process.env.CI,
+        },
+      }
+    : {}),
+  projects: [
+    {
+      name: 'chromium',
+      use: { ...devices['Desktop Chrome'] },
+    },
+  ],
+});