research: compare Jev intent state with the previous turn

V0 on the existing 157 real rows matches the 09-19 cache. The staging extract has no case linkage, so V1/V2 are unmeasured and the verdict stays 缺数据.

scripts/research/jev_intent_samples/README.md

@@ -15,7 +15,9 @@ sha256: `79d53a958b3b42ed18c79e3bbcff4b31deb22b65eedcd89b39326a7fefc9b0e8`
 ```sql
 select
   t.id as turn_id,
+  t.case_id,
   t.user_message,
+  t.assistant_message,
   t.status as turn_status,
   t.created_at,
   c.status as case_status,
@@ -24,16 +26,23 @@ select
   f.status as focus_status
 from public.agentic_rectification_turns t
 join public.agentic_rectification_cases c on c.id = t.case_id
-left join public.agentic_rectification_conversation_focuses f
-  on f.case_id = t.case_id
- and f.status = 'active'
+left join lateral (
+  select *
+  from public.agentic_rectification_conversation_focuses f
+  where f.case_id = t.case_id
+    and f.asked_at <= t.created_at
+  order by f.asked_at desc
+  limit 1
+) f on true
 where t.user_message is not null
   and length(btrim(t.user_message)) > 0
-order by t.created_at desc
-limit 500;
+order by t.case_id, t.created_at;
 ```
 
+同一条 SQL 也写在 `scripts/research/jev_intent_source_b_v2.py` 的 `EXTRACT_SQL`。本地脚本按 `(case_id, created_at)` 给每条填 `previous_turn = {assistant_message, user_message}`；同一案件的第一轮，以及没有 `case_id` 的行，都是 `null`。没有 `case_id` 的行不会互相串成上一轮。
+
 - 本地路径（worktree 外，已 gitignore）：`G:/Ferti/Jyotisha/.cache/jev_intent/source_b.jsonl`
+- v2 路径（同样不提交）：`G:/Ferti/Jyotisha/.cache/jev_intent/source_b_v2.jsonl`
 - 本机抽取条数：157（点选 17 / 采集 107 / 无焦点 33），gold 已全部人工标注，未用模型代标
 - 长度：P25=12 / 中位=21 / P75=28 / 最长=172
 - 标注耗时：约 40 分钟（`runtime_intent` 只作参考，85 条有反推 intent，不抄成 gold）