fix: resolve circular dependency by removing comfyPageFixture re-export

- Remove comfyPageFixture re-export from ComfyPage.ts
- Update all test imports to use comfyPageFixture from its own file
- Update README.md example to show correct import path
- Fixes: comfyPageFixture → LocalhostComfyPage → ComfyPage circular import

browser_tests/tests/sidebar/queue.spec.ts

@@ -1,6 +1,6 @@
 import { expect } from '@playwright/test'
 
-import { comfyPageFixture as test } from '../../fixtures/ComfyPage'
+import { comfyPageFixture as test } from '../../fixtures/comfyPageFixture'
 
 test.describe.skip('Queue sidebar', () => {
   test.beforeEach(async ({ comfyPage }) => {