A pure read counts the issues the crew parked in the last 24 hours and 7 days, and names the newest three #6471

Parked work is the plan's waste: an issue a builder tried and could not finish. The owner should see how much there is without reading comments.

Done:

• [ ] src/flow/parked.ts exports readParked(db, now, publicOnly), which returns { day, week, newest: { repo, issue, title }[] }. A parked issue is an open issue whose newest comment starts with Parked by the crew. It counts by that comment's time, and newest holds at most 3.
• [ ] test/flow-parked.test.ts seeds a parked issue from today, one from 3 days ago, one from 10 days ago, a closed parked issue and an issue with a later comment after the park. The counts come out as 1 and 2. publicOnly hides a private repository's issue.

Files: src/flow/parked.ts, test/flow-parked.test.ts