Keep Jira issues current with live Bugsnag error numbers

**Objective:** Bring the Jira issue tracking Bugsnag error {error-id} up to date by posting the error's current state as a single comment, including a sample of {event-sample-size} recent occurrences (default 3).

**Step 1: Read the current error state (bugsnag server)**

Call `bugsnag-get-error` filtered by error-id {error-id}. Keep status, severity, events, users, first-seen-date, last-seen-date, release-stages, error-class, message and error-url. If nothing comes back, report that the error no longer exists and stop.

**Step 2: Sample recent occurrences (bugsnag server)**

Call `bugsnag-get-event` filtered by error-id {error-id} with max-records set to {event-sample-size}, defaulting to 3. Keep received-at-date, app-version, app-release-stage, context, file, request-url and unhandled. If there are no events, continue and say so in the comment.

**Step 3: Find the tracking issue (jira server)**

Call `jira-get-issue` filtered by project-key {jira-project-key} and summary containing {error-id}. Keep the issue id, issue-key, status and assignee. If nothing comes back, stop and tell the user no Jira issue tracks this error, and that link-error-to-new-jira-issue will create one.

**Step 4: Confirm, then comment once (jira server)**

Show the user the comment body and the issue key, and wait for approval. Then call `jira-add-issue-comment` exactly once with that issue id. The body should carry: current Bugsnag status and severity, total events, affected users, first and last seen dates, the release stages affected, the sampled occurrences, and the Bugsnag error url.

**Step 5: Report**

State the issue key commented on, and flag the mismatch if the Jira issue status is Done while the Bugsnag error is still open, or the reverse.

**Rules & Guidelines:**

* `bugsnag-get-error` and `bugsnag-get-event` are on the bugsnag server. `jira-get-issue` and `jira-add-issue-comment` are on the jira server. All three servers must be connected.
* Post one comment. Never call `jira-add-issue-comment` twice in a run, and never call `jira-update-issue-comment` to rewrite somebody else's comment.
* Do not change anything else. Do not call `jira-update-issue`, `jira-assign-issue`, `bugsnag-fix-error`, `bugsnag-ignore-error` or `bugsnag-update-error-severity`.

**Validation:**

* If `jira-get-issue` returns more than one issue mentioning the error id, list them and ask which to comment on rather than picking one.
* If the sampled events and the error disagree on release stage or app version, report both rather than reconciling them yourself.