ci: add quality-gate workflow, ESLint and Playwright smoke test

playwright.config.ts

@@ -0,0 +1,21 @@
+import { defineConfig, devices } from "@playwright/test";
+
+const PORT = 4173;
+
+export default defineConfig({
+  testDir: "./e2e",
+  workers: 1,
+  retries: process.env.CI ? 1 : 0,
+  reporter: "list",
+  use: {
+    baseURL: `http://localhost:${PORT}`,
+  },
+  projects: [{ name: "chromium", use: { ...devices["Desktop Chrome"] } }],
+  // Serves the production build (run `npm run build` first).
+  webServer: {
+    command: `npx vite preview --port ${PORT} --strictPort`,
+    url: `http://localhost:${PORT}`,
+    reuseExistingServer: !process.env.CI,
+    timeout: 60_000,
+  },
+});