fix(tests): resolve dialog button selector issues in Playwright tests

- Fix 50-record-offer.spec.ts multiple alert button conflict
  * Replace generic alert selector with success-specific selector
  * Use getByRole('alert').filter({ hasText: 'Success' }) pattern

- Fix 20-create-project.spec.ts onboarding dialog timeout
  * Replace unreliable div > svg.fa-xmark selector
  * Use established closeOnboardingAndFinish testId pattern
  * Add waitForFunction to ensure dialog dismissal

- Fix 25-create-project-x10.spec.ts onboarding dialog timeout
  * Apply same onboarding dismissal pattern as other tests
  * Ensure consistent dialog handling across test suite

These fixes use established patterns from working tests to resolve
6 failing tests caused by UI selector conflicts and timing issues.

test-playwright/20-create-project.spec.ts

@@ -107,8 +107,11 @@ test('Create new project, then search for it', async ({ page }) => {
 
   // Create new project
   await page.goto('./projects');
-  // close onboarding, but not with a click to go to the main screen
-  await page.locator('div > svg.fa-xmark').click();
+  // close onboarding using established pattern
+  await page.getByTestId('closeOnboardingAndFinish').click();
+  await page.waitForFunction(() => {
+    return !document.querySelector('.dialog-overlay');
+  }, { timeout: 5000 });
   await page.locator('button > svg.fa-plus').click();
   await page.getByPlaceholder('Idea Name').fill(finalTitle);
   await page.getByPlaceholder('Description').fill(finalDescription);