fix(rectification): persist refresh attempts and map collect focus kinds (BUG-656/657/658)

Empty engine refresh now records an already_answered attempt so GET can leave wait-to-narrow; collect kinds map onto the table CHECK; remaining candidates drive probe refresh.

Co-authored-by: Cursor <cursoragent@cursor.com>

docs/tasks/PROGRESS-rectification-targeted-collect-persist-fix-20260911.md

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+# 进度 · 修复单：采集焦点 kind、剩余候选刷新、刷新尝试落库（2026-09-12）
+
+## 范围
+
+- 分支：`codex/rectification-targeted-collect-persist-fix-20260911`（基于 `origin/staging` @ `2b6d28e7`）
+- 任务单：`docs/tasks/TASK-rectification-targeted-collect-persist-fix-20260911.md`
+- BUG-656：采集焦点 `kind` 映射到表 CHECK
+- BUG-657：引擎刷新按剩余候选
+- BUG-658：刷新尝试落库、等待收窄按已问过判定、落库失败同一事务出卡
+- T1 与 T3 不可省；T2 已一并做完
+
+## 完成
+
+- T1 `collectFocusTargetKind`：`targeted:` / `anchor:` / `generic:` 写入 CHECK 枚举；原 hint 进 `collect_kind`
+- T2 `build_refinement_packet`：`refresh_probes` 且 `column_times` 非空时用剩余分钟生成探针；回执 `refresh_result`
+- T3 `refresh_attempts` 以 `already_answered` 持久化；`refreshExhausted` / `shouldRefreshDatedPool` 同源；定向 persist `skipped` 出「目前范围」；`collect_waiting` 覆盖无 stopReason 的采集缺口
+- T4 BUG-656～658、CHANGELOG、本文件、场景 0c
+
+## 验收（本机，未部署）
+
+- `frontend` `tsc --noEmit` 0 错
+- eslint 变更文件 0 error（既有 unused-import warning 仍在）
+- `rectification-server-focus.test.ts` + `rectification-probe-pool-exhausted-20260911.test.ts` + `rectification-surface-state.test.ts` + `rectification-replay-20260911.test.ts`：**51 / 51**
+- Python：`test_candidate_discriminator_contract.py` + `test_rectification_event_probes.py`，fail=0（`.venv/bin/python -m pytest`）
+
+## 未做
+
+- 未 commit / 未 push
+- 未部署后按场景 0c 真机走一遍