Add Playwright configuration and initial tests for landing page

- Created playwright.config.ts for test configuration
- Added .last-run.json to store test run status
- Implemented landing.test.ts with tests for navbar visibility and navigation
- Removed unused server proxy configuration from vite.config.ts

tests/landing.test.ts

@@ -0,0 +1,21 @@
+import { test, expect } from "@playwright/test";
+
+test("landing page shows navbar and account info", async ({ page }) => {
+  await page.goto("/");
+
+  // Check navbar is visible
+  await expect(page.locator("nav >> text=AITrader")).toBeVisible();
+  await expect(page.locator("text=Stocks")).toBeVisible();
+  
+  // Check account info is displayed
+  await expect(page.locator("text=Trading Account")).toBeVisible();
+  await expect(page.locator("text=Cash")).toBeVisible();
+  await expect(page.locator("text=Buying Power")).toBeVisible();
+  await expect(page.locator("text=Portfolio Value")).toBeVisible();
+});
+
+test("navigation to stocks works", async ({ page }) => {
+  await page.goto("/");
+  await page.click("text=Stocks");
+  await expect(page).toHaveURL("/stocks");
+});