Fix CI JS corruption from obfuscator stdout; clean up flaky test guards

- Strip [javascript-obfuscator-cli] progress line from elc --obfuscate
  output before writing to dist/js/ (was prepended to every compiled JS
  file, causing browser parse errors on stage)
- Remove spurious waitForFunction(signUpWithEmail) guards from
  buyer-name and buyer-email structural tests (pure DOM tests, no auth)
- Switch chat.spec.ts beforeEach to domcontentloaded (SSR elements
  present at DOM ready; networkidle caused cold-start timeouts)

tests/e2e/checkout-stripe.spec.ts

@@ -186,7 +186,6 @@ test('[professional] payment-message div starts hidden', async ({ page }) => {
 
 test('[professional] buyer-name input is present and fillable', async ({ page }) => {
   await page.goto('/checkout?plan=professional');
-  await page.waitForFunction(() => typeof (window as any).signUpWithEmail === 'function', { timeout: 10000 });
   await expect(page.locator('#buyer-name')).toBeAttached();
   await page.fill('#buyer-name', 'Test User');
   expect(await page.locator('#buyer-name').inputValue()).toBe('Test User');
@@ -194,7 +193,6 @@ test('[professional] buyer-name input is present and fillable', async ({ page })
 
 test('[professional] buyer-email input is present and fillable', async ({ page }) => {
   await page.goto('/checkout?plan=professional');
-  await page.waitForFunction(() => typeof (window as any).signUpWithEmail === 'function', { timeout: 10000 });
   await expect(page.locator('#buyer-email')).toBeAttached();
   await page.fill('#buyer-email', 'test@example.com');
   expect(await page.locator('#buyer-email').inputValue()).toBe('test@example.com');