[bug] miners API: CLOSED pull requests filtered by created_at instead of closed_at

[kiannidev]

Description

GET/POST /api/v1/miners/:githubId/pulls applies inconsistent time windows across PR states. MERGED PRs correctly use merged_at >= since. CLOSED (unmerged) PRs use created_at >= since, while the sibling /issues endpoint uses closed_at >= since for closed issues. Old PRs closed inside the scoring window but opened before since are omitted from miner pull results.

Steps to Reproduce

1. Mirror a repo with a miner-authored PR: created_at = 60 days ago, closed_at = 5 days ago, state = CLOSED (not merged).
2. Call GET /api/v1/miners/{authorId}/pulls?since= (ISO timestamp 30 days ago).
3. Call GET /api/v1/miners/{authorId}/issues?since= (same timestamp).
4. The closed issue appears (closed_at >= since); the closed PR does not (created_at < since).
5. Repeat with POST .../pulls and since_by_repo — same filter in getPullRequestsByRepo.

Expected Behavior

CLOSED PRs should enter the window when closed_at >= since, matching issues and matching how MERGED uses merged_at.

Actual Behavior

(p.state = 'CLOSED' AND p.created_at >= $2)   -- should use closed_at

Environment

• OS: Linux
• Runtime/Node version: Node 20

[kiannidev]

Addressed in PR #184.

[anderdc]

CLOSED PRs are windowed by created_at by design — the /issues parallel doesn't hold because issues have no merged state and don't feed the credibility ratio. Working as intended. Closing.