Add Playwright test infrastructure for wxWidgets WASM port

- Add tests/ directory with Playwright e2e tests
- Add minimal wxWidgets WASM test application
- Add build script for test app (scripts/build-wasm-test.sh)
- Update wxWidgets submodule with WASM build fixes
- Update .gitignore for test artifacts

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

tests/e2e/wxwidgets.spec.ts

@@ -0,0 +1,70 @@
+import { test, expect } from '@playwright/test';
+
+test.describe('wxWidgets WASM', () => {
+  test('app loads without JavaScript errors', async ({ page }) => {
+    const errors: string[] = [];
+    page.on('pageerror', err => errors.push(err.message));
+    page.on('console', msg => {
+      if (msg.type() === 'error') {
+        errors.push(msg.text());
+      }
+    });
+
+    await page.goto('/minimal_test.html');
+
+    // Wait for WASM to initialize (canvas becomes visible)
+    await page.waitForSelector('canvas', { state: 'visible', timeout: 30000 });
+
+    // Give it a moment to settle
+    await page.waitForTimeout(1000);
+
+    // Filter out known non-critical errors
+    const criticalErrors = errors.filter(e =>
+      !e.includes('SharedArrayBuffer') && // COOP/COEP warning
+      !e.includes('cross-origin')
+    );
+
+    expect(criticalErrors).toHaveLength(0);
+  });
+
+  test('canvas element is rendered with dimensions', async ({ page }) => {
+    await page.goto('/minimal_test.html');
+
+    const canvas = page.locator('canvas');
+    await expect(canvas).toBeVisible({ timeout: 30000 });
+
+    // Canvas should have non-zero dimensions
+    const box = await canvas.boundingBox();
+    expect(box).not.toBeNull();
+    expect(box?.width).toBeGreaterThan(0);
+    expect(box?.height).toBeGreaterThan(0);
+  });
+
+  test('loading progress completes', async ({ page }) => {
+    await page.goto('/minimal_test.html');
+
+    // Progress text should eventually show completion or disappear
+    await page.waitForFunction(() => {
+      const status = document.getElementById('progress-text');
+      if (!status) return true;
+      const text = status.textContent || '';
+      return text.toLowerCase().includes('complete') ||
+             text === '' ||
+             status.style.display === 'none';
+    }, { timeout: 30000 });
+  });
+
+  test('WASM module initializes successfully', async ({ page }) => {
+    await page.goto('/minimal_test.html');
+
+    // Wait for canvas to be visible (indicates WASM loaded)
+    await page.waitForSelector('canvas', { state: 'visible', timeout: 30000 });
+
+    // Check that the Module object exists and is initialized
+    const moduleExists = await page.evaluate(() => {
+      return typeof (window as any).Module !== 'undefined';
+    });
+
+    expect(moduleExists).toBe(true);
+  });
+});