Reopen a Bugsnag error when Zendesk tickets say it is back

**Objective:** Decide whether Bugsnag error `{error-id}` should be reopened because Zendesk tickets about it are still arriving, looking at the last `{lookback-days}` days (default 7).

**Step 1: Read the error**

Call `bugsnag-get-error` with error-id `{error-id}`. If nothing comes back, stop. If its status is already open, report that there is nothing to reopen and stop. Otherwise note its status, message, context, project-name and last-seen-date.

Call `bugsnag-get-project` with `name` set to the error's project-name to get its project-id.

**Step 2: Look for fresh evidence on both sides**

On Bugsnag: call `bugsnag-get-event` with `error-id` `{error-id}` and `received.from` set to `{lookback-days}` days ago. Count the events.

On Zendesk: pick 1 to 3 short customer-facing fragments from the error's message and context and call `zendesk-get-ticket` with `subject.contains` set to each and `created.from` set to `{lookback-days}` days ago. Confirm each likely match with `zendesk-get-ticket-comment`.

**Step 3: Decide**

Recommend reopening only when there is confirmed evidence: at least one confirmed ticket in the window, or recent Bugsnag events. If Bugsnag shows recent events but no ticket confirms them, say so; if tickets confirm it but Bugsnag has no events, say the error may be being reported under a different error-id and suggest searching with `bugsnag-get-error` by message.

Show the evidence (event count, confirmed ticket-ids with subject and created-date) and the recommendation. If recommending a reopen, ask the user to confirm. Do not write anything until they do.

**Step 4: Reopen, once**

If confirmed, call `bugsnag-open-error` once with `error-id` `{error-id}` and the project-id from Step 1. Then call `bugsnag-get-error` again and confirm the status is open.

**Step 5: Report**

The decision, the evidence behind it, and the ticket-ids an engineer should read.

**Rules & Guidelines:**

* `bugsnag-get-error`, `bugsnag-get-project`, `bugsnag-get-event` and `bugsnag-open-error` are on the bugsnag server. `zendesk-get-ticket` and `zendesk-get-ticket-comment` are on the zendesk server.
* The only permitted write is one `bugsnag-open-error` call, after confirmation. Do NOT call `bugsnag-update-error-severity`, `bugsnag-assign-error`, `bugsnag-discard-error`, `zendesk-update-ticket`, `zendesk-add-ticket-comment` or any other write tool.

**Validation:**

* An error that was discarded drops new events, so zero events is expected for it. Rely on the tickets and say why.
* If neither side has evidence, report that the fix is holding and stop.
* Pass dates as YYYY-MM-DD.