fix(pull): allow re-request after stale review request

[lunny]

What changed

• Determine review-request idempotency from the reviewer's latest meaningful review by ID, including comment reviews.
• Lazily replace stale review-request rows when a newer comment, approval, or rejection exists.
• Preserve the existing lookup semantics for removing review requests and for closed or merged pull request guards.
• Add regression coverage for idempotency, stale request recovery, comment-only history, and closed pull request behavior.

Why

Legacy or imported data can contain an old ReviewTypeRequest row alongside a newer ReviewTypeComment row. The sidebar treats the newer comment as the current state, while AddReviewRequest previously ignored comments and silently returned after finding the stale request. As a result, re-requesting a review appeared to do nothing.

This change repairs the inconsistent state through the normal application path without requiring a migration or a doctor command.

Verification

• go test ./models/issues/...
• go test ./models/...
• go test ./services/issue/...
• go build ./...
• go vet ./models/issues/...
• make fmt
• git diff --check

make lint-go could not complete because the local go-critic ruleguard loader panics while loading fmt. The same panic reproduces on the unmodified base commit.

---

Generated by Codet