fix: generate JSON reports alongside HTML for test count extraction

- Add JSON reporter to Playwright test runs
- Generate report.json alongside HTML reports
- Store JSON report in playwright-report directory
- This enables accurate test count extraction from CI artifacts

The HTML reports alone don't contain easily extractable test statistics
as they use a React app with dynamically loaded data. JSON reports
provide direct access to test counts.

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

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

.github/workflows/test-ui.yaml

@@ -229,8 +229,10 @@ jobs:
 
       - name: Run Playwright tests (${{ matrix.browser }})
         id: playwright
-        run: npx playwright test --project=${{ matrix.browser }} --reporter=html
+        run: npx playwright test --project=${{ matrix.browser }} --reporter=html --reporter=json
         working-directory: ComfyUI_frontend
+        env:
+          PLAYWRIGHT_JSON_OUTPUT_NAME: playwright-report/report.json
 
       - uses: actions/upload-artifact@v4
         if: always()
@@ -275,8 +277,13 @@ jobs:
           merge-multiple: true
 
       - name: Merge into HTML Report
-        run: npx playwright merge-reports --reporter html ./all-blob-reports
+        run: |
+          npx playwright merge-reports --reporter html --reporter json ./all-blob-reports
+          # Move JSON report to the HTML report directory for easier access
+          [ -f "report.json" ] && mv report.json playwright-report/report.json
         working-directory: ComfyUI_frontend
+        env:
+          PLAYWRIGHT_JSON_OUTPUT_NAME: report.json
 
       - name: Upload HTML report
         uses: actions/upload-artifact@v4