docs: explain compare API use case for local automation

Author: root

docs/browser-use-debugging.html

@@ -423,6 +423,7 @@ <h2 id="compare-run-metadata-checklist">Compare failed and successful Browser Us
 browsertrace compare &lt;failed_run_id&gt; &lt;success_run_id&gt; --json</code></pre>
       <p>While the local BrowserTrace UI is running, local wrappers and tools can request the same first-divergence payload through the web API:</p>
       <pre><code>curl http://127.0.0.1:3000/api/compare/&lt;failed_run_id&gt;/&lt;success_run_id&gt;</code></pre>
+      <p>The API endpoint is useful for local dashboards, scripts, or automation preflight checks that need the same first-divergence JSON payload.</p>
       <p>Example compare output:</p>
       <pre><code>$ browsertrace compare failed-local-html-upload good-local-html-upload
 First divergent step: 3

tests/test_metadata.py

@@ -4004,6 +4004,8 @@ def test_browser_use_guide_documents_compare_run_metadata_checklist():
     )
     assert "local BrowserTrace UI is running" in section
     assert "same first-divergence payload" in section
+    assert "local dashboards, scripts, or automation preflight checks" in section
+    assert "same first-divergence JSON payload" in section
     assert "first divergent step" in section
     assert "Example compare output:" in section
     assert "$ browsertrace compare failed-local-html-upload good-local-html-upload" in section