Add second PR reviewer self-improvement gold batch

[Wenjie Fan (gggdttt)]

Summary

• add 14 vetted code-review gold concepts from BCApps PRs 9067, 7938, and 8553
• rewrite the disputed UI-handler, actionable ErrorInfo, exhaustive-case, API-widening, and progress/DeleteAll boundaries to match Refine self-improvement review guidance BCQuality#132 at 5f1cff2fb6427c14cf9b2ef1f790ee404a144b9e
• correct synthetic__perf-batched-commit-checkpoint-01 to use exact next-N retrieval with TopNumberOfRows, a temporary key buffer, and a same-transaction persisted watermark
• keep the five rejected concepts out of the production dataset

Validation

• loaded all 144 entries through CodeReviewEntry.load; all instance IDs are unique
• parsed all 15 changed patches and verified expected comments target added lines
• applied both real BCApps modification patches against base commit 397d01199c321e774edaf23a7290fee40f75c6a6
• uv run pytest -q tests/test_codereview.py tests/test_collect_codereview.py tests/test_codereview_judge_calibration.py (105 passed, 1 skipped)
• uv run pre-commit run --files dataset/codereview.jsonl