chore: install Playwright and add E2E test configuration

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

playwright.config.ts

@@ -0,0 +1,26 @@
+import { defineConfig, devices } from "@playwright/test";
+
+export default defineConfig({
+	testDir: "./e2e",
+	fullyParallel: false,
+	retries: 0,
+	workers: 1,
+	reporter: "list",
+	globalSetup: "./e2e/global-setup.ts",
+	use: {
+		baseURL: "http://localhost:3000",
+		trace: "on-first-retry",
+	},
+	projects: [
+		{
+			name: "chromium",
+			use: { ...devices["Desktop Chrome"] },
+		},
+	],
+	webServer: {
+		command: "DATABASE_PATH=./e2e/test.db bun run dev:server",
+		port: 3000,
+		reuseExistingServer: !process.env.CI,
+		timeout: 10000,
+	},
+});