fix(#13): fix GitHub issue/comment scraping for stale repos

[rbalogic]

Summary

Fixes partial GitHub activity ingestion for repositories that had stale repository.updated_at timestamps, which could cause valid recent issue/comment activity to be skipped.

Changes

• Removed the early skip gate based on repo.updated_at < since
• Updated GitHub issue fetching to include both OPEN and CLOSED states
• Made scrape lookback window configurable via config.scrapeDays or SCRAPE_DAYS
• Added issue #13 handoff notes, including verification and backfill guidance

Context

Resolves #13, where recent issue_opened and commented activities from ohcnetwork/design were missing while other activity types (e.g. pr_opened) continued to update.

Verification

• Ran node --check plugins/github.js
• Verified reported missing events using gh API:
  • ohcnetwork/design#92 (issue opened)
  • recent comment activity on ohcnetwork/design#85

Follow-up

Run a manual scrape with a wider lookback window (for example, days: 30) to backfill already-missed April 2026 events.

[rbalogic]

@rithviknishad Please review the changes when you can, Thanks.