fix(sweep): paginate issue events and honor unlabeled when closing expired issues

[fcarvajalbrown]

Problem

closeExpired() in scripts/sweep.ts decides whether to auto-close an issue by finding when its lifecycle label (invalid / needs-repro / needs-info / stale / autoclose) was applied:

const events = await githubRequest<any[]>(`${base}/events?per_page=100`);
const labeledAt = events
  .filter((e) => e.event === "labeled" && e.label?.name === label)
  .map((e) => new Date(e.created_at))
  .pop();
if (!labeledAt || labeledAt > cutoff) continue;

Two correctness bugs, both on high-visibility issues:

1. Pagination. The issue events endpoint is paginated (default 30, max 100 per page) and returns events oldest-first (verified empirically against a live issue). This reads only page 1. On a busy issue the lifecycle label is applied late in the issue's life, so it lives on a later page and is never fetched. labeledAt is undefined, the issue is skipped, and its event count only grows, so it is skipped forever. The busiest issues never auto-close.
2. Ignores unlabeled. The code only inspects labeled events. If a label was applied early, removed, then re-applied recently, it closes the issue against the old application time even though the grace period restarted, a premature close with a "Closing for now" comment and state_reason: "not_planned" on an active thread.

The other issue-list fetches in this file already loop pages; only the per-issue events fetch did not.

Fix

• fetchLabelEvents() walks every event page (natural end, plus a 10-page cap consistent with the existing loops).
• A pure, source-agnostic helper scripts/label-events.ts reconstructs the label's current state from the full labeled/unlabeled stream, sorted by created_at rather than trusting the endpoint's undocumented order, and returns the most recent still-active application time (or null if the label is no longer applied).
• closeExpired() uses shouldClose(); downstream behavior (comments-since window, dry-run age) is unchanged.

Tests

scripts/label-events.test.ts (Bun), 5 passing:

• label applied on page 2 (>100 events) is still detected;
• labeled -> unlabeled -> re-labeled recently uses the recent timestamp, not the old one;
• labeled -> unlabeled and not re-applied is treated as not currently labeled;
• plus label-isolation and empty-input cases.

The old logic was confirmed failing on the same inputs (page-2 case returned "don't close"; removed-label case returned "close"), and passing after.

Also

scripts/auto-close-duplicates.ts set the duplicate label through the issue PATCH, whose labels field replaces the entire set and therefore wiped any pre-existing labels (bug, area:*, priority, ...). It now adds the label through the labels endpoint, which merges.

[muhmadkwazulugorilla-png]

oh wow you are so brown