feat(learning): שער-אישור ל-decision_lessons — רק לקח מאושר זורם לכותב (INV-LRN1, #126)

אודיט #122 חשף שלקחי-הפאנל (decision_lessons) זרמו לכותב אוטומטית
(block_writer → get_recent_decision_lessons) ללא סינון-אישור — הפאנל כתב,
והכותב צרך מיד, בעקיפת שער-היו"ר (INV-LRN1/G10). מנגד, מה שהיו"ר אישר ב-promote
הלך לערוץ נפרד (appeal_type_rules). תוצאה: דליפה — תוכן לא-מאושר השפיע על הכתיבה.

התיקון — שער-אישור מפורש:
- עמודת review_status (proposed|approved|rejected) ל-decision_lessons (SCHEMA_V34).
- get_recent_decision_lessons (צרכן-הכותב) מחזיר רק review_status='approved'.
- הפאנל (style_lesson_panel) כותב 'proposed' (ברירת-מחדל) → לא זורם עד אישור.
- לקח שהיו"ר מקליד ידנית ב-/training = 'approved' מיידית (מדלג על שער-ההצעה).
- UI (lessons-tab, טאב "קורפוס" ב-/training): תג-סטטוס + כפתורי אשר/דחה/בטל-אישור.

הכרעת-יו"ר (2026-06-11): כל הלקחים שקדמו לשער (41) מתאפסים ל-'proposed' —
שום לקח לא זורם עד אישור מפורש (ברירת-המחדל של העמודה מיישמת זאת על הקיימים).

Invariants:
- INV-LRN1 / G10 (מקיים) — עדכון-ידע לערוץ-הכותב דורש אישור-יו"ר מפורש; אין auto-commit.
- INV-LRN5 (נשמר) — substance ממילא מסונן בפאנל; השער הוא על style_method בלבד.
- G1 (מקיים) — סינון-במקור (get_recent) ולא תיקון-בקריאה אצל הכותב.
- G2 (מקיים) — אותו פנקס decision_lessons; אין מסלול מקביל.

api:types: להריץ npm run api:types אחרי deploy (review_status נוסף ל-payload;
הטיפוסים הידניים ב-training.ts כבר מעודכנים, tsc עובר).

ref: #122 · #126 · data/audit/learning-loop-activity-20260611.md

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

mcp-server/src/legal_mcp/services/db.py

@@ -1442,6 +1442,19 @@ CREATE TABLE IF NOT EXISTS drain_controls (
 );
 """
 
+SCHEMA_V34_SQL = """
+-- decision_lessons review gate (INV-LRN1/G10): a lesson must be chair-APPROVED
+-- before it flows to the writer. The style panel writes proposals
+-- (review_status='proposed'); get_recent_decision_lessons (writer-consumed) returns
+-- only 'approved'. The chair approves/rejects in /training. Existing rows take the
+-- column default — per chair decision (2026-06-11) all pre-gate lessons reset to
+-- 'proposed' (nothing flows until re-approved).
+ALTER TABLE decision_lessons
+    ADD COLUMN IF NOT EXISTS review_status TEXT NOT NULL DEFAULT 'proposed';
+CREATE INDEX IF NOT EXISTS idx_decision_lessons_review
+    ON decision_lessons(review_status);
+"""
+
 
 async def _run_schema_migrations(pool: asyncpg.Pool) -> None:
     async with pool.acquire() as conn:
@@ -1479,6 +1492,7 @@ async def _run_schema_migrations(pool: asyncpg.Pool) -> None:
         await conn.execute(SCHEMA_V31_SQL)
         await conn.execute(SCHEMA_V32_SQL)
         await conn.execute(SCHEMA_V33_SQL)
+        await conn.execute(SCHEMA_V34_SQL)
     logger.info("Database schema initialized (v1-v33)")
 
 
@@ -2257,7 +2271,7 @@ async def list_decision_lessons(corpus_id: UUID) -> list[dict]:
     async with pool.acquire() as conn:
         rows = await conn.fetch(
             "SELECT id, style_corpus_id, lesson_text, category, source, "
-            "       applied_to_skill, created_by, created_at, updated_at "
+            "       applied_to_skill, review_status, created_by, created_at, updated_at "
             "FROM decision_lessons WHERE style_corpus_id = $1 "
             "ORDER BY created_at DESC",
             corpus_id,
@@ -2272,16 +2286,20 @@ async def add_decision_lesson(
     category: str = "general",
     source: str = "manual",
     created_by: str = "chaim",
+    review_status: str = "proposed",
 ) -> dict:
+    # review_status gate (INV-LRN1/G10): panel-written lessons default to 'proposed'
+    # and do NOT flow to the writer until the chair approves. A lesson the chair
+    # authors directly is passed review_status='approved' by the caller.
     pool = await get_pool()
     async with pool.acquire() as conn:
         row = await conn.fetchrow(
             "INSERT INTO decision_lessons "
-            "(style_corpus_id, lesson_text, category, source, created_by) "
-            "VALUES ($1, $2, $3, $4, $5) "
+            "(style_corpus_id, lesson_text, category, source, created_by, review_status) "
+            "VALUES ($1, $2, $3, $4, $5, $6) "
             "RETURNING id, style_corpus_id, lesson_text, category, source, "
-            "          applied_to_skill, created_by, created_at, updated_at",
-            corpus_id, lesson_text, category, source, created_by,
+            "          applied_to_skill, review_status, created_by, created_at, updated_at",
+            corpus_id, lesson_text, category, source, created_by, review_status,
         )
     return dict(row) if row else {}
 
@@ -2292,6 +2310,7 @@ async def update_decision_lesson(
     lesson_text: str | None = None,
     category: str | None = None,
     applied_to_skill: bool | None = None,
+    review_status: str | None = None,
 ) -> dict:
     sets: dict = {}
     if lesson_text is not None:
@@ -2300,6 +2319,8 @@ async def update_decision_lesson(
         sets["category"] = category
     if applied_to_skill is not None:
         sets["applied_to_skill"] = applied_to_skill
+    if review_status is not None:
+        sets["review_status"] = review_status
     if not sets:
         return {"updated": False, "reason": "nothing to update"}
     sets["updated_at"] = "now()"  # sentinel — replaced inline below
@@ -2312,7 +2333,7 @@ async def update_decision_lesson(
         row = await conn.fetchrow(
             f"UPDATE decision_lessons SET {set_clause} WHERE id = $1 "
             f"RETURNING id, style_corpus_id, lesson_text, category, source, "
-            f"          applied_to_skill, updated_at",
+            f"          applied_to_skill, review_status, updated_at",
             lesson_id, *values,
         )
     if not row:
@@ -2494,7 +2515,12 @@ async def get_methodology_overrides(category: str) -> dict:
 
 async def get_recent_decision_lessons(limit: int = 15, practice_area: str = "") -> list[dict]:
     """Per-decision learnings the chair/curator attached in /training (decision_lessons),
-    so the writer consumes them too (T15). Prefers style/structure/lexicon, recent first."""
+    so the writer consumes them too (T15). Prefers style/structure/lexicon, recent first.
+
+    Gate (INV-LRN1/G10): returns only CHAIR-APPROVED lessons (review_status='approved').
+    Panel-written proposals stay out of the writer's context until the chair approves
+    them in /training — the chair's review is the gate, not the panel's 2/2 vote.
+    """
     pool = await get_pool()
     async with pool.acquire() as conn:
         rows = await conn.fetch(
@@ -2502,7 +2528,8 @@ async def get_recent_decision_lessons(limit: int = 15, practice_area: str = "")
                       sc.decision_number, sc.practice_area
                FROM decision_lessons dl
                JOIN style_corpus sc ON sc.id = dl.style_corpus_id
-               WHERE ($2 = '' OR sc.practice_area = $2)
+               WHERE dl.review_status = 'approved'
+                 AND ($2 = '' OR sc.practice_area = $2)
                ORDER BY dl.created_at DESC
                LIMIT $1""",
             limit, practice_area,