Find the change that broke a browser test

**Objective:** Explain why the Ghost Inspector test matching `{test-name}` started failing by finding what changed in Azure DevOps in the `{lookback-days}` days (default 7) before its first failure.

**Step 1: Find the test and its first failure (ghost-inspector)**

Call `ghost-inspector-get-test` with `name.contains` set to `{test-name}`. If more than one test matches, list them and stop. Then call `ghost-inspector-get-test-result` with that `test-id`, newest first, and walk back through the results to find the oldest run in the current unbroken run of failures. Record its `date-created`. If the test is passing now, say so and stop.

**Step 2: Find what changed before that moment (azure-devops)**

Using the first-failure time as the cut-off and `{lookback-days}` days before it as the start:

* Call `azure-devops-get-commit` with `author-date.from` and `author-date.to` and list commits with author, comment and `commit-id`.
* Call `azure-devops-get-pull-request` with `status` set to completed and keep those whose `closed-date` is inside the window.
* Call `azure-devops-get-pipeline-run` and keep runs whose `finished-date` is inside the window, noting `result`.

**Step 3: Report**

The test, its first failing run and time. Then a timeline of changes, newest first, ending at the first failure. Mark as candidates the changes closest to the failure, and any failed pipeline run. Match the test's `start-url` or name against pull request titles and commit comments, and flag any that mention the same page or feature.

**Rules & Guidelines:**

* Azure DevOps tools (prefix azure-devops-) come from the azure-devops server; Ghost Inspector tools (prefix ghost-inspector-) come from the ghost-inspector server. Both servers must be connected.
* The systems share no key; the only link is time plus any shared words. Present candidates, not a verdict.
* Do not call any write tool: `ghost-inspector-execute-test`, `ghost-inspector-execute-suite`, `ghost-inspector-execute-on-demand-test`, `ghost-inspector-update-test`, `ghost-inspector-update-suite`, `ghost-inspector-add-test-result-comment`, `ghost-inspector-add-suite-result-comment`, `ghost-inspector-accept-screenshot`, or any create, duplicate, cancel or update tool. This prompt only reads.
* Do not call any Azure DevOps tool other than the get tools named above.

**Validation:**

* If no changes are found in the window, say so and suggest widening `{lookback-days}`.
* If the test has never passed, say the failure may predate any change.